Video Game / Hearts of Iron

aka: Hearts Of Iron II

"The Pope! How many divisions has he got?"

— Joseph Stalin

A series of World War II Grand Strategy Simulation Games by Paradox Interactive. The games allow players to take the role of virtually any country on Earth as of the time at the beginning of the games' various scenarios.

The series currently consists of :

• Hearts of Iron (2002)
• Hearts of Iron II (2005)
  • Has two expansions: Doomsday and Armageddon
  • As well as two official updated version/add-ons: Arsenal of Democracy, and Iron Cross
  • Another update which includes World War I has been released: Darkest Hour
• Hearts of Iron III (2009)
  • Has received four download-only expansions: Semper Fi, Dies Irae: Gotterdammerung (a Germany-focused mod for Semper Fi), For the Motherland (which breaks compatibility with DI:G), and Their Finest Hour.
• Hearts of Iron IV, released on 6 June 2016. It currently has 4 free expansions and 6 paid expansions.
  • Poland: United and Ready (6 June 2016), a free DLC pack available on launch day that includes unique content for Poland.
  • Together for Victory (15 December 2016), the Torch update, which adds new content for the majority of the Commonwealth nations (Canada, Australia, New Zealand, South Africa, and the British Raj), as well as a new system for puppeting nations. This DLC was made free to all players from March 21, 2024, with integration in the base game scheduled for a future update.
  • Death or Dishonor (14 June 2017), the Oak update, which adds new content for most of the Balkan nations (Czechoslovakia, Hungary, Romania, and Yugoslavia), as well as new diplomatic options for fascist countries and new equipment production options. This DLC was made free to all players from March 21, 2024, with integration in the base game scheduled for a future update.
  • Waking the Tiger (8 March 2018), the Cornflakes update, which adds/revises content for Germany, China, Manchukuo, and Japan, including the various Chinese warlords, as well as new general abilities to add more flexibility to combat. This DLC was made free to all players from March 21, 2024, with integration in the base game scheduled for a future update.
  • Man the Guns (28 February 2019), the Ironclad, Hydra, and Fork updates, which adds/revises content for the United States, the United Kingdom, Mexico, and the Netherlands, as well as adjustments to naval combat and a new Ship Designer.
  • La Resistance (25 February 2020), the Husky update, which adds/revises content for Spain (including every faction in the Spanish Civil War), France (including Free France and Vichy France), and Portugal, as well as a brand new system of espionage to undermine foreign nations.
  • Battle for the Bosporus (15 October 2020), the Collie update, which adds new content for the remaining Balkan nations other than Albania (Bulgaria, Greece, and Turkey).
  • No Step Back (23 November 2021), the Barbarossa update, which adds/revises content for the USSR, Poland, Estonia, Latvia, and Lithuania, as well as a completely overhauled logistics system, a military spirit designer, and a new Tank Designer.
  • By Blood Alone (27 September 2022), the Avalanche update, which adds/revises content for Italy, Ethiopia, and Switzerland, as well as an overhauled peace deal system, adjustments to the Ship Designer, an embargo system, and a new Plane Designer. With this update, every major nation from game launch received revised content
  • Arms Against Tyranny (10 October 2023), the Stella Polaris update, which adds new content for the Nordic countries (Finland, Sweden, Norway, Denmark, and Iceland), as well as a new Military Industrial Organization system, a special forces overhaul, and an international arms market mechanic. Finland's historical focus tree was also made available to players without the DLC.
  • Trial of Allegiance (7 March 2024), the Bolivar patch, which adds new content for Brazil, Argentina, Chile, Paraguay, and Uruguay.

The games have a large modding scene actively encouraged by the developers; some of the more prominent of those can be found here.

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This video game series provides examples of:

• Acceptable Breaks from Reality: Many of the political focuses in IV, such as Britain turning fascist/communist, Trotsky returning to USSR and Germany returning to monarchy would've taken Alien Space Bats to succeed post-1936, but are featured in the game because it's more fun to give players more alternative scenarios. Modeling political events beginning in, say, the year 1920 would be extremely difficult, as well as demanding on hardware, since the game is known to have problems with just reaching its 1949 end date on acceptable frame rates.
• Ace Pilot: In IV, there is a chance to generate those during air engagements. Ace attached to an air wing increase its performance in specific missions. Aces themselves are tiered, with the basic one representing what Ace Pilot is in Real Life, while tier 3 comes with Improbable Piloting Skills, Improbable Aiming Skills and make the entire air wing perform as if it was fitted with lesser aces.
• Adapted Out: Despite being the primary casus belii for the United States joining the war, the 1941 Pearl Harbor attack is absent from in-game events.^note The US used to have a focus based around Pearl Harbor that would give Japan a war goal against them, but it was removed after Man the Guns. In-game, Japan's main method of drawing the United States into the war is instead declaring war on the Phillipines, whose independence is guaranteed by the latter.
• Alternate History:
  • A major marketing point of the series, the game allows for things as big as the USA having a revolution in response to the Great Depression (you can choose whether to become Socialist, Fascist, Communist, or something else), to events as small as a historically-neutral country joining a certain side (Spain/Turkey/Argentina/Portugal joining the Axis or Allies, Brazil joining the Comintern, the USA joining the Allies before 1941, etc).
  • The second expansion for HoI2, Armageddon, features a full-on alternate history as one of its campaigns. Nations include the United States of North America (US/Canada), the Confederates being independent and owning Mexico, a communist Britain that controls the low countries and Denmark, a communist Japanese republic, Russia still being a monarchy, Prussia still being an independent nation, and many others.
  • IV gives players the option to choose whether the AI will pursue historical options (Molotov-Ribbentrop Pact, Barbarossa, etc.) or whether it can go off the rails even without player intervention. For example, Germany and Poland reaching a peaceful resolution over Danzig or Japan deciding to look to Siberia for expansion rather than the Pacific. Additionally, with the right ministers, you can reform Germany into a democracy. With Waking the Tiger Paradox has begun to add in added alternate-historical branches as DLC material accompanying patches that modify the base tree — such as adding in options for Germany to go Imperial German or democratic German Empire or Japan going communist or returning to democracy, or Puyi's Manchukuo restoring Imperial China after rebelling against Japan.
  • IV's trailers occasionally venture into this. One of the trailers for Waking the Tiger refers to an upcoming invasion of Japan by the Soviet Union. The Battle for the Bosporus trailer shows an aerial bombing of Istanbul happening in 1941; historically, Turkey did not join World War II until February 1945 when the conflict was almost over.
• Alternate History Wank: Any good player will cause this in the nation they play as: Germany conquering the Soviet Union and the world, Japan conquering China, France or even Poland holding off the Nazi tide, the red flag flying over all of Europe, the United States conquering the Soviet Union and Germany, a boatload of historically neutral nations (Argentina, Sweden, Turkey, Afghanistan, Saudi Arabia, Iran, Spain, and so on) joining either side, the Republicans winning the Spanish Civil War (either the main faction, or after a takeover by the anarchists), WWII lasting beyond 1945, the Nationalists winning the Chinese civil war, etc. Anything is possible. Hearts of Iron 4 provides even wilder scenarios and plotlines in shape of focus trees, such as Turkey coring Finland because their lineage can be traced back to Ural-Altay tribes.
  • IV makes it even easier by including an option in Custom Settings to increase the strength of certain nations, giving them coded-in boosts to pretty much everything- less supply consumption, faster experience gain, more political power, and so on. So if you want to see Germany, Italy, the Soviet Union, France, the United Kingdom, the United States, Japan, or China become a global superpower, you don't even have to play as them- just give them the boost, pick an out-of-the-way country and watch the show.
• Anarchy Is Chaos: The La Résistance expansion for IV adds the ability to play as an anarchist faction should you choose a specific focus tree path as Republican Spain. This fittingly drops your national stability to 0%, but you get several bonuses which compensate or cancel the negative effects of this; an anarchist state will never have its workers go on strike for example. The goal of the anarchists, after rebranding the nation to the "Regional Defence Council of Iberia" and later the "Global Defence Council", is to convert other nations to anarchism through both force and encouraging uprisings in other countries. Meanwhile, the entire world considers you as having crossed the Moral Event Horizon and will target you if not fully occupied with another war, while your army is effectively made up of volunteers, and you have major penalties to earning political power within the Defence Council's jurisdiction. Good luck.
  • In the second game and its expansions, it’s possible to play as the “Guerilla” faction, which is only spawn-able in regions that have achieved a state of anarchy after continuous warfare. They are not meant to be played, so more of a Self-Imposed Challenge.
• A Nazi by Any Other Name: The Generic Nazism subideology of Fascism in "IV".
• Argentina Is Nazi-Land: In IV, Germany can start a civil war to try to oust the Nazi leadership. If the rebels win, Hitler will be assumed to be dead. However, Hitler has a chance of not actually dying and instead escaping to the Americas, and can even come to power as a Fascist leader in Argentina as Señor Hilter or in USA as Adam Hilt.
• Armor Is Useless: Subverted. The games actively encourages getting as much hardness and armour rating for your units as only feasible. Once enemy forces are unable to pierce your units, you can survive against improbable odds without taking (almost) any damage. And starting from III, units that the enemy can't pierce gain a combat bonus.
• Artificial Stupidity: The AI isn't completely stupid, but has a number of fairly obvious failings, some of which were covered up by bending the rules a bit. The AI is particularly deficient in the second installment when it comes to nuclear weapons:
  • AI nations will never develop nuclear weapons, as it was not written into their code.
  • AI nations that start with nukes (such as in the Doomsday scenario) will use them immediately against anyone they are at war with, regardless of how many their target has, ethical considerations, or if they even need to.
  • Possessing nukes will not act as a deterrent to the AI, nor will using them make a country any more likely to surrender. Similarly, other countries will not care if you use nukes, regardless of who you attack or with how many. Though they are not as much of a Game-Breaker in this game as they were in Real Life (particularly because they cannot be mass-produced), it is uncharacteristically ahistorical for there to be no political effects at all from the use of nuclear weapons. However, being nuked does raise dissent in the attacked nation, to the point that five or so nukes would completely remove its effective industrial capacity, even if majority of industry is still intact. Furthermore, Darkest Hour adds surrender events for nuked Japan, Soviet Union, United Kingdom, and USA.
  • AI doesn't really understand the importance of strong industrial base, regardless of game. In II and Darkest Hour that meant AI had issues with production of everything and had subpar research, as those relied on IC counter - and often suffered from units having supply issues, as those are related with IC. In III that meant pushing most of IC into making of expensive units, without leaving enough of it to also improve the industry; nor it tried to improve its practical knowledge for construction, instead bee-lining expensive and hard-to-build factories directly. In IV AI not only will focus from the get-go on construction of military factories (so not investing in civilian ones, responsible for construction of everything else), it will also gladly convert civilian factories into military ones, further slowing construction of new buildings - and all of that while during peace-time.
    • And following this pattern, AI also can't do upgrades. In II and III it is very eager to make models that will be obsolete with next few weeks thanks to research and then spends full upgrade costs to directly upgrade the newly produced unit into newest technology - basically producing the same unit twice. Since AI can't allocate its existing capacity nor prioritise, this means there will be even less IC for production, while insufficient amount to upgrade in any meaningful quantity. In IV, this is made even worse, as all hardware is produced separately, meaning AI will first spend months into pumping out already obsolete gear and then instantly switch to newest possible model the day the tech is researched, losing all production efficiency in doing so and ending up with no meaningful quantity being delivered to troops. If this happens during a war and stockpile of old models wasn't big enough to compensate, it can break a nation.
  • The AI does not seem to comprehend the value of turning its piles of divisions into proper units, leading to stacks of a hundred small units (frequently hodgepodged from expeditionary forces around the world) with atrocious organizational value that will get steamrolled by a player organized army with laughable ease. However, in case of countries like Nationalist China, Italy or Manchukuo this is intentional - and when player is controlling them, first few minutes are spend on re-arranging existing army into something useful out of the historical mess.
    • Additionally, in II and III, the AI is overly cautious, leading to long drawn out deadlocks with nothing happening when faced with large stacks that it really should be able to break through. In an Axis South America game this can be seen quite clearly by putting a few dozen divisions at the narrower points of Central America and witnessing American forces several times your size just standing there even though they should by all rights win, or in Italy where the Axis can deadlock Comintern or Allied forces for ages on end.
  • Aside of being cautious in general, AI has a tendency to try to ignore provinces with fortification. That's all good and well, but the problem is the inability to evaluate the fortifications themselves. For an AI-controlled nation, it makes no difference if it's a level 1 pillbox that can be rolled over without slowing down or a level 10 fortress, as both will be considered equally dangerous to engage.
  • In III, many nations (notably the UK, USA, and Japan) do not defend their ports at all, leading to them being laughably easy to conquer if one can defeat or outmaneuver their respective navies. This was patched in later expansions, for better or for worse.
  • Also in III, the Soviet Union in a 1936 game will often build tons of reserve divisions, which are divisions kept at half-strength until mobilization. While the huge number of divisions it fields may look imposing (often hundreds), when Germany declares war on the Soviets, mobilization will completely deplete its manpower attempting to fill them all up (as Germany's already full-strength army hits them like a Mack truck). Predictably, this leads to the Red Army's full-scale collapse.
  • In IV the AI is basically completely incapable of managing the war in the Pacific; both the UK/US and the Japanese AIs. Or more specifically it is completely incapable of managing the amphibious landing part, with both the Allied and Axis AIs leaving islands that were historically bled over untouched and at worst no amphibious landings will take place at all while the IJN fights indecisively with the American and British navies, waging entirely pointless battles. While this has been alleviated somewhat, the Pacific War is widely regarded as the most weakly modeled aspect of WWII where the AI's incompetence at naval landings and warfare come to a head. And you can forget about anyone trying to land on the Japanese Home Islands without the player in the driver's seat. This can lead to World War II going on basically forever as no one bothers to actually deliver the knockout blows to Japan and whatever islands it does take once it's booted out of the continent.
  • In some games in IV, the AI will simply forget how to build tanks and train armoured battalions (even if you lend-lease them tanks), resulting in a bizarre scenario where, outside of player-controlled nations, tanks have become a Lost Technology, with the only the ones that existed when the game started being used. Since this means that the only counter the AI has to armour is, at best, towed anti-tank guns, this turns the already Game Breaking Heavy Tank battalions into super weapons.
    • In similar vein, if a country is not scripted to use them, it will never form air wings of naval and strategic bombers, even if they are leased to it. Some countries are also unable to make wings of heavy fighters and most of minors are prone to field Close-Air Support far away from frontlines, making them barely useful in combat. AI has also serious issues with managing its carrier air groups, usually overstaffing them with single type of plane (and often that type is CAS, which are only good for shore bombardment).
  • Sometimes, in IV, if you take some of an AI nation's territory while at war with them, they will endlessly attack your entrenched front lines until they run out of manpower and supplies, after which you can effortlessly push for capitulation.
  • AI is very bad at making trade deals. It often proposes deals unfavourable to both sides or at least the AI and rarely takes into account such minor factors like diplomatic relation value or distance (and thus requirement for convoys). In IV it additionally has absolutely zero strategical input toward making deals, often leading to situation like Germany buying resources from Allies before the war (thus giving away own industrial capacity to future enemies) or Romania trading oil with everyone, but Axis members.
  • Also in IV, the AI will recruit divisions pretty much forever so long as it has more than a pittance of manpower in reserve and with almost no regard to its equipment situation, and it never disbands divisions once they're recruited. As a result, the AI tends to make a massive, poorly equipped army that shatters after suffering even minor losses because its divisions soon can't get any manpower or rifles to reinforce. Not helping matters is that infantry equipment is one of the handful of techs that has top AI priority, which means that the AI will frequently change out production lines, losing production efficiency and switching to models that cost more industrial capacity per item, and worse, more steel. It's not unheard of for the AI to have four million men in the field and be over a hundred thousand infantry equipment in the red (that's a million rifles since each infantry equipment represents gear for ten soldiers) before it's fought a single battle.
  • The AI will never switch templates - while this might not seem like that big of a deal at first, it comes across as this if the AI has to fight a player in a civil war, where forces will be split when the war starts - meaning that if the player disbands their entire army and spawns a bunch of units with little to no HP (i.e., only consisting of 1 division of artillery) before the war, the AI will stubbornly use these units, while the player's troops (which are likely better equipped) will kill the AI units with ease.
  • The AI is more than happy to kick a player from their faction if they generate too much tension (this is only an issue for Democratic-led factions), but they'll never revoke military access - even if they would be called in to war against the player.
  • The Soviet Union is more than happy to sign the Molotov Ribbentrop Pact...even if Poland is a member of the Axis or Comintern, and the Pact does not kick Poland from either faction^note as is the case with Austria if Germany does the Anschluss - because of how high the country's starting popularity of Fascism is, it would be very easy to flip and join the Axis to avoid being annexed - thus resulting in the AI immediately declaring war on the leader of whichever faction Poland is a part of.
  • The 4 "major" factions (Allies, Axis, Comintern, and the Chinese United Front) are more than happy to invite countries belonging to their respective ideologies (Democracy, Fascism, Communism, and Non-Aligned) if said countries are independent and not already in a faction...even if they're at war, which can result in situations like the Soviets getting dragged in to the Sino-Japanese War because Sinkiang joined the Comintern while fighting Japan.
  • The AI will never declare war on countries it doesn't have a war goal on (and won't justify on countries that don't control territory that is claimed by an AI nation or is a core of an AI nation), and if those countries aren't called in, can't be fought^note the game actually does give countries a way around this - if a country is at war with another country, they can declare on a puppet without justifying a war goal on them - i.e., Germany can declare war on Australia if Germany is at war with the United Kingdom. This means that if e.g. France releases Tunisia as a puppet at the start of the game, the Italians will put forces on Libya's border with Tunisia, even if Tunisia doesn't have any troops present in the area.
  • The British AI will ship most of its divisions off to fight in the colonies, particularly in IV, leaving behind only a scant few to defend the Home Islands. As soon as the English channel is secured, a mere handful of divisions can conquer the whole island.
• Artistic License – Economics: Industrial capacity. It's allocated purely for balance issues and is in no way an accurate depiction of world industrial capacity at the time. If it was, the USA would have 40%, the Soviet Union and Germany with maybe 14% each (though both would expand rapidly as the years roll on, with Germany reviving its industry and devouring most of Europe and the Soviets still frantically industrializing), Britain with 10% (not including industrialized parts of the Empire like South Africa, Canada, and Australia), France with 4%, Japan with 3.5%, Italy with 2.5% and the rest of the world with 10% combined. The logistics system in II is also extremely unrealistic in that it is completely perfect - there are no supply problems, ever, apart from the underproduction or isolation. Hearts of Iron 3 makes some improvement on this, but logistics problems are still severely under-estimated.
  • IV takes a step further, removing the more complex logistics system of III and only offering the equivalent of the previous game's simplified "Arcade" logistics system. It also steps down in another area, as it gets rid of the all purpose "Supplies" resource used in the previous games (and until Man the Guns DLC, also fuel), meaning units can fight indefinitely, as long as they have at least one supply line to the capital. It does however require separate production lines to produce individual vehicles, planes, and weaponry, but in the same time abstracts the Industrial Capacity even further, with split between civilian and military factories and relatively easy was to catch up with the big dogs, as a single factory has now much bigger value for the whole industry.
    • With the Barbarossa update and No Step Back, the complexity of IV's logistics massively increased. Now, supplies have to be taken down rail lines by trains, then distributed from supply hubs that can be assigned varying levels of motorization, and the rail lines need to be optimized to prevent supplies from being help up on inadequate sections of track and protected so enemy forces can't cut supply lines by holding a single province of rail.
• Artistic License – History: Has enough examples for its own page.
• As Long as It Sounds Foreign: Or, in this case, looks foreign. Comintern nations in the third installment will have their names written in faux-Cyrillic on the map. This led to a fair amount of complaining from Cyrillic reading fans and wasn't kept in the sequel. As usual, there's a Game Mod to change this.
• Attack! Attack! Attack!: With III's Their Finest Hour expansion, you can set a general's aggression level. At maximum, he's likely to pick extremely aggressive tactics, including "Reckless Assault" which gives the attacker a 50% bonus to damage, at the cost of taking 25% more damage from the defender. This aggression can backfire, though, if a skilled defending general picks the ideal counter-tactic, effectively blunting the entire assault and killing huge numbers of attackers.
• Autobots, Rock Out!: If you’re playing with the Sabaton music pack enabled, expect this trope to be invoked by the ingame radio plenty.
• Awesome, but Impractical:
  • Super-heavy armor, strategic rockets, and super-battleships tend to be like this. However, when deployed properly, they can be quite effective. Also, strategic rockets can attach nukes to them, creating an ersatz MRBM nuclear missile.
  • Nuclear weapons in II fall into this trope more often than not. They can only be unlocked after a long, difficult research chain that offers no other benefits, and can only be produced one at a time after building a hugely expensive test reactor. Only nations with plenty of industrial capacity and a tech team that specializes in nuclear technology can even consider them. Of course, scenarios where nuclear weapons are already available are the exception.
    • In III, the test nuclear reactor you must build does supply power, making it not entirely useless. That said, if you're a nation that can afford the nuclear tech tree (i.e. a first or second-tier power), in all likelihood you're not hard up for electricity.
    • In IV, the reactors you build only produce nuclear weapons over time - fortunately, the tech that unlocks the reactors is separate from nukes, meaning it's plausible to have a few reactors build by the time you unlock nukes, but this creates two other problems: first, you need air superiority and strategic bombers that have range of the target (not an easy feat, especially if up against a nation with a large industrial base like Germany or the USSR; they specifically need to be strategic bombers, which can't fit on aircraft carriers), and second, the reactors only start generating nuclear bombs after you unlock nukes - and have a very slow amount. And before you think you can just make more, they have some of the highest construction costs, at a time when you'll probably have needs for other buildings (like refineries or military factories).
  • Battalions that can be attached to divisions in II border on this and Cool, but Inefficient - most of them provide meaningless bonus or are outright useless. The few that are actually useful show up too late to make any real difference or are still underpowered in relation to their price, required research and build time. It was somewhat fixed in Darkest Hour, but only to certain degree. The only exeption might be towed artillery, but only when added to Marines and Paratroopers - they need every single bonus they can get, as there is limited amount of troops you can use for amphibious assault and paradrops, while mobility isn't an issue for them at all.
  • Ships powered by nuclear reactors. They show up very late into the game, require a lot of hard and time-consuming research and then obviously have to be build first. Only a handful of countries can even consider the entire process and all of them are better off with just regular navy, since the actual benefits of nuclear propulsion aren't even remotely close to the various expenses and most importantly time it takes to get navy outfitted with it. And a single ship with reactor is a meaningless addition, since regular units are going to drag it down with their speed and range.
    • To a lesser extent, late game naval units qualify in each game. Aside from screens and submarines, everything else takes just too much time to be build, so most navies will be composed from early 40s models and the entire research process for further upgrades isn't usually worth the effort, as the units won't be deployed before early '46 mark. By that point, naval warfare is usually long resolved, too. And naval bombers are cheaper anyway.
  • In IV, mechanized infantry eventually trumps everything else on land. They have infantry-level hit points, armored vehicle armor, enough antitank capability to blow through panzer armor, and speed that equals that of motorized infantry. However, they are by far one of the most expensive things to field. It takes a lot of industrial production and resources, to the point a single mechanized vehicle costs as much production as 5 trucks or most advanced model of a medium tank. And most importantly, the mechanized infantry only gets really useful with the final, third technology, set for 1944 for research, otherwise being lackluster, but still extremely expensive to make. It all makes them impractical to research and produce before the war is usually already done with and the actual benefits of deploying tier III mechanized vs. plain motorised^note which most countries already produce in 1936 are cosmetic. And having 4 division of tanks supported by motorised is always better than having one of tanks with mechanized infantry, not to mention other ways of spending all the saved production. Man the Guns DLC made mechanized even more impractical, since now motorised infantry can be deployed with motorised artillery^note which is using the same artillery pieces as infantry, greatly boosting motorised units without increasing their production costs at all and without any additional research being required - while mechanized gain... bigger fuel usage.
  • Amphibious tanks and tractors take everything awesome but impractical about mechanized and add even more to both the awesomeness and impracticality - they have considerable bonuses in naval invasions, river crossings, and marsh combat like marines, but also like marines, their deployment is limited by the special forces cap. Additionally, basic amphibious tanks are only a little better than 1934 light tanks and much slower and advanced amphibious tanks are only slightly better than 1939 medium tanks while being 1940 and 1942 technology respectively, they're more expensive than regular armor, and they're more fuel hungry. Amphibious tractors are more statistically competitive with mechanized, but they lack the third level (which also passively gives mechanized better hard and soft attack), are just as painfully expensive as mechanized, and they use as much fuel as the amphibious tanks, making them huge fuel hogs for what is essentially situationally better mechanized.
  • Rocket artillery and motorized rocket artillery - they're more powerful than conventional artillery, but they require heavy additional technological investment to be worthwhile and don't benefit from the common artillery designer, but rather the rocket theorist which many countries simply do not have, and as they start as 1940 tech, they often only come into play once you're already at war and need your existing production to remain in full swing, making it inconvenient to get them into production in the first place, and towed rocket artillery requires two units of tungsten where normal artillery calls for only one. Still, they have some niche uses - towed rocket artillery requires only one steel where tube artillery calls for two or three, making it suitable for countries like India that have larger reserves of tungsten than steel, and rocket and tube artillery are separate support companies, so a division can have both. Also, motorized rocket artillery requires no tungsten at all, only steel and rubber like regular motorized, and it has the highest soft attack of any artillery outside of heavy, super-heavy, and modern self-propelled artillery, once fully invested in.
  • Those super-battleships you just built are pretty nice, and will probably beat any smaller ship it goes up against very nicely. But they come with three big problems. First, they are prohibitively expensive, costing tens of thousands of production, when you can only assign a few dockyards to them. Second, they are very slow and highly visible, the two things which decreases its evasion chance in combat; you're going to have to surround it with screening ships and cover it in AA guns unless you don't mind it getting torpedoed to the bottom of the sea. Third, they take forever to repair: fully repairing a damaged battleship can take almost a year. And because of the second reason, it tends to take lots of smaller hits from weaker weaponry, which can take months to bring it back to ship-shape. And God help you if it takes a Critical Hit, because that debuff isn't going away until it's repaired completely.
  • Mountaineers. They are your Elite Mooks that excel at mountain combat and... not much else. In fact, being light infantry, they are worse than regular troops. In all games they are in, they require separate research to even field and upgrade them, they are more expensive to make and don't do much. Taken a notch higher in IV with the post-WTT gameplay changes, as they are also limited in number, rather than being freely recruited. All of this is Truth in Television - many armies, after the experience of WW1, decide that they really need dedicated troops to fight in the mountains, observing the Italian Alpine front. Came WW2 and the front was moving so fast, mountain troops were unable to keep up with it and even deploy properly - most armies disbanded their mountain infantry post-war and never reactivated them, reducing them to just a single battalion of specialists.
• Balkanize Me: China is represented as an alliance of several warlord factions (the Nationalists and Communists are just two among many) essentially functioning as an Enemy Mine to defend against Japan.
• Blatant Lies: In IV, the British Raj/India has the "Agrarian Society" national spirit, which reduces the recruitable population by 69% due to local traditions that make the drafting of farmers unacceptable. The game describes it thus: "This belief is so wide-spread and well-entreched that it will require at least a generation to overcome", which suggests that there is some way to remove it. However, until a 2022 balance update (which added a long series of decisions to remove it), it was actually impossible to remove this from India, not even by changing ideology, winning independence, or winning a civil war (as both sides would always have the spirit).
  • However, there has always been a way to get rid of this spirit if you aren't playing as the Raj: Pakistan, Burma, and Bangladesh will not have this spirit if you satellite them as puppets, and if you form a collaboration government from the British Raj, said collaboration government won't have the spirit.
• Blessed with Suck: Central Planning side of the economy slider in II and especially Darkest Hour. It provides a huge bonus to raw IC (+15 when the bonus activates, ending at +25%) along with a massive decrease of consumer goods demand (up to -20%). However, at the same time, it also increases upgrade costs up to +25%, which in practice means you're going to spend far more IC than you gain each time you're upgrading your land forces. And the bonus IC you gain requires resources to operate, which you don't get for free. Meanwhile, the Free Market side of the slider provides you with staggering -20% production and -25% upgrade costs, making the IC you already have far, far more efficient, without generating demand for resources, too. Darkest Hour takes it a step further, since you can adjust your sliders only once every two years, while a variety of profitable and useful decisions are going to push your slider one step toward Central Planning whenever taken.
• Boring Yet Practical:
  • Infantry: versatile and for the most part doesn't require fuel or any other resource besides manpower, which, unfortunately, they eat like nothing else. With Their Finest Hour, infantry are actually required for any Combined Arms bonus. You can have all the tanks, artillery, and other specialized brigades you want, but without infantry, motorized infantry, or mechanized infantry, they get no bonus at all. Furthermore, militia do not count as infantry for Combined Arms.
  • Towed artillery, especially in Darkest Hour and IV, is an overkill for soft targets (like infantry) for almost no price. Compared with all other things you can research and build, those are just a handful of field guns and howitzers that punch really hard, are very cheap to produce and even easier to research. Excluding III, certain upgrades don't even require direct replacement of the already fielded pieces, making them all that cheaper to operate.
  • Garrisons in games that have them. A single garrison division is better at suppressing partisans and resistance activity than presence of few other divisions, meaning you can focus your army on frontlines, rather than chasing ghosts in some forest or mountains. They are also good enough to secure beachheads from naval invasions thanks to combination of entrenching and the countless debuffs invading troops are under. They are also very cheap and fast to train, as they are essentially barely-trained guards armed with surplus rifles.
  • Ministers decreasing foot infantry and artillery costs, by the virtue of making all three above units types cheaper and faster to train. This might mean skipping on people providing either combat bonuses or specialists dealing in more advanced unit types, but when 90% of your troops are going to be the standard issue infantry, you need the boring minister that simply makes it easier to field.
  • In II and III any minister that decreases the amount of consumer goods needed or dissent growth rate, no matter what other options you have for their spot, is the best choice. Their bonus might not be particularly strong or big, and it doesn't affect your military directly... but it allows to squeeze more IC for military, as it reduces the minimal number of factories needed to provide consumer goods. It's nothing fancy, but adds up really fast, especially if you need to do a build-up or massive upgrades.
  • Military police companies in IV - they're not flashy and don't have any particularly neat effects for combat divisions like engineers or recon and don't have the raw stats of support artillery, but especially with the integrated support branch of the Superior Firepower doctrine, they are the absolute most IC-efficient source of soft attack in the game, and do so at no combat width cost, and have manpower efficiency only surpassed by artillery. With the integrated support bonuses, they're essentially an entire additional infantry battalion that takes no frontage and only uses half as many rifles and half as much manpower.
• Break Out the Museum Piece:
  • Darkest Hour has a set of decisions offering an option to buy obsolete hardware from other countries, netting dated airplanes, tanks and even battleships. They are rarely anything more modern than mid-20s, but in a pinch, even that can be useful.
  • Indian Revive the Screw Guns focus from IV, which puts back to service 7-pounder Mountain Gun, a late 19th century light artillery that was originally designed as a support for troops operating in rough terrain. The description also mentions that while it is by all means obsolete technologically, it doesn't make it any less useful in mountains.
  • This can also happen naturally if your game stretches past the 40s and you inflict so much damage on the enemy that they resort to using starting equipment from the 30s again.
• Character Portrait: Almost every general and every minister for every country in the world has one. They aren't always perfectly accurate, but the effort the development team went through is still very impressive, especially considering how much less information and images were available online when the first and second installments were being made during the first part of the noughties.
• Cheese-Eating Surrender Monkeys: Sometimes averted, sometimes played straight, depending on how the game evolves. With the most recent version of III, France (as per Paradox Interactive tradition) is somewhat of a monster.
• Chess Motif: Puppet states in IV use icons of chess pieces to denote their level of autonomy - countries denoted by a pawn are one step from being annexed outright, countries represented by queens are almost fully independent, while countries on intermediate tiers are represented by rooks, knights, and bishops. Waking the Tiger adds a separate puppet system for Japan, which are represented by Shōgi pieces instead.
• Command & Conquer Economy: Pretty much a Justified Trope, especially for countries like Germany or the USSR. You can mandate new industrial development and allocate amounts of industrial capacity points to the areas of consumer goods, production, supplies, reinforcements and upgrades, with boosts or penalties to said industrial economy with certain minister types in your cabinet, whether you are at war and what choices you make in some events.
• Commie Nazis: The literal version can happen in IV. After signing the Molotov-Ribbentrop Pact, Germany can invite the USSR into its faction, disbanding both the Axis and Comintern and creating the 'Berlin-Moscow Axis' in their place. Unsurprisingly, this horrifies pretty much everyone else in the world, especially other fascists. The effects of forming the Berlin-Moscow Axis are so bad that a fascist/communist America can return to democracy immediately, while Britain rallies every last democratic nation on Earth to form the Grand Alliance faction as protection from the new Axis.
• The Computer Is a Cheating Bastard: In II the AI can see everything; it can carry out amphibious assaults anywhere on the globe; and its organisation regenerates while moving. It can also materialise massive fleets that weren't anywhere on the map or in any port a moment ago when you checked with the nofog cheat to make sure there weren't any nasty surprises waiting for your amphibious assault somewhere.
• Cool, but Inefficient:
  • Heavy cruisers, just like in real life. They never pack enough guns and enough armour to be a real "big" ship, but in the same time cost too much to just mass produce them as fodder. Made even more explicit in III and IV, where players can customise their ships and still there is just no way to make heavy cruisers worth their price and construction time other than III's exploit to make actual battleships cheaper.
    • Subverted in IV with post-MtG, but before BBA patches. In that period, heavy cruiser was instead turned into a floating light artillery platform, and it turns from the most useless to the most powerful capital ship, for it shreds through enemy screens and making easy openings for torpedo attacks.
  • In II, on paper, Central Planning is great for your war industry. It provides a huge bonus to raw IC (+15 and even +25%) along with massive decrease of consumer goods demand (up to -20%). However, in the same time it also increases upgrade costs up to +25%, which in practice means you're going to spend far more IC than you gain each time you're upgrading your land forces. Meanwhile, free market side of the slider provides you with staggering -20% production and -25% upgrade costs, making the IC you already have far, far more efficient, without generating demand for resources, too.
  • Unless your nation is spending more than 50% of its total Industrial Capacity on production of supplies, any minister that provides bonuses to supply production is this - due to plethora of factors^note Raw supply production, technological level, efficiency, demand, size of total IC, difficulty level etc., their bonus will be so small, it won't matter at all. Doubly so if you are making only just enough supplies to provide for your existing forces and not building up surplus. If you have alternative to this, pick it.
  • Similarly, ministers that provide discount on tanks and mobile infantry are this. If you're playing as a nation who can afford those, the -5% discout won't matter one bit. If you're playing as a nation struggling to get those into production, why are you even trying, especially if you're skipping a minister providing discount to infantry and artillery?
• Cool Plane: As if air superiority in the series wasn't deadly enough, you have the option of researching air-to-air missiles, jet engines, radars, radar-guided bombs and missiles, and Rocket Interceptors. (All perfectly period appropriate, by the way.) Focusing on such advanced techs can give you quite the edge in air battles, especially if you also upgrade your AA defenses to fire surface-to-air missiles.
• Cool Ship: Advanced Super-Heavy Battleships, topped only by Nuclear Battleships.
• Crippling Overspecialization: Rocket interceptors are very, very good at shooting down bombers in small air zones, as they are dirt cheap, have incredible speed, monstrous air attack, and very high agility that keeps them from getting clobbered by light fighter escorts like heavy fighters might. They also cannot do anything else - they can only run the interception mission, which does not generate air superiority, so they can't control airspace to directly benefit ground units (though shooting down enemy planes is an indirect bonus to that), and they're useless in large air zones because the maximum range of the top of the line rocket interceptor III is 750 km, meaning that outside small European and North/Central American air zones (and even then, only really when operated from centrally-located air bases), their efficiency will suffer badly. Additionally, the first two levels have very low base reliability (30% for rocket interceptor I and 50% for rocket interceptor II, while rocket interceptor III and all other planes have a base reliability of 80%).
• Cue the Flying Pigs: IV's waiting screen occasionally quotes one of Hermann Göring's more famous (and far less foresighted) boasts, then decides to have some fun with it.
  "No Enemy bomber can reach the Ruhr. If one reaches the Ruhr, my name is not Göring. You can call me Meyer." - Hermann Meyer
• Cyanide Pill: One of the upgrade available to your intelligence agency. It increases the chance your spies die when captured (which seems counterproductive, but serves to reduce the risk of them changing their allegiance to the enemy).
• Deal with the Devil: If you're Republican Spain and playing the Democratic faction, you'll find Soviet aid to be this. It can be very helpful in winning the civil war and recovering from the aftermath, but read the fine print: After the Civil War, Spain becomes a Soviet puppet. If you're the Stalinists, the same thing happens, but Stalin's more willing to let Spain be a partner in the Comintern instead of a vassal.
• Delaying Action:
  • With the correct doctrine, or luck, defenders can activate a "Delay" event, which slows down the attacking sides advance and penalizes the attackers chances of causing casualties to the defenders, for a slight reduction to the defenders own chances.
  • This is basically the player's strategy for France, holding off the Germans until the British (and later the Americans) show up. How well it works depends heavily on you.
• Design-It-Yourself Equipment:
  • III had a limited scope for this, mostly used by naval units, as players had full control over which components were put in during production. Planes and tanks were always set for using the most recent components, which could still be controlled by simply (not) researching specific things.
  • DLCs for IV introduced designers for ships, tanks and planes, allowing to tailor them either for specific tasks, or, much more often, exploit various loopholes in gameplay mechanics and meta. Even without DLCs, experience can be used to alter hardware of related type, providing variants with slightly different stats than the baseline models. The AI is notoriously incapable of using either of those systems, completely messing up DLC-backed designs (since there are no "default" models) and treating regular variants as endless experience sinks for no real benefits.
• Developer's Foresight: In IV, the United States have alternate history decisions which allow to turn Alaska, Hawaii, and Puerto Rico into states^note the former received this status out of the scope of the game (respectively in 1959 and 1960), while the latter still had another status when the game was released. If those decisions are taken while USA are democratic (non-democratic USA have different flags, devoid of the rectangle filled with stars), the flag will be altered to reflect the new states with up to three new stars.
  • Certain countries have industrial/military focuses that are available regardless of what political branch they go down. If the player opts to go down a branch that changes their government, the names of said focuses will change to something more fitting of said government^note i.e., the German focus "Kd F Wagen" will become "Wilhelm Wagen" if Germany overthrows Hitler and restores the Kaiser.
    • Similarly, some political focuses have effects that will change if the original conditions weren't able to be executed but they aren't bypassed - for example, one of Greece's focuses on their historical/monarchist path is "Achieving Enosis", which under normal circumstances, allows for Greece to request that the British return the island of Cyprus to them. However, if Cyprus exists in the world (either through Britain decolonizing, or through a country liberating Cyprus from the British in a peace deal), Greece can instead suggest Enosis to Cyprus instead. Likewise, the "Blum Violette Proposal" focus on the French tree normally just grants France cores on Algeria, but if France released the nation as a puppet, France will annex them first before gaining the cores.
• Difficult, but Awesome: Just like in real life, paratroopers. If used incorrectly or you don't relieve them in time, a poorly executed para-drop can cost you tens, if not hundreds, of thousands of casualities. But with proper use and a little bit of luck, you can instantly capitulate enemy countries with a single drop. In IV, by far the easiest way to capitulate the Allies before 1939 as Germany is to para-drop Britain and France before their militaries are ready for war.
  • The Spanish Anarchists in IV are this mixed with Magikarp Power. Your "national" Stability is permanently set to 0%. Your military is by far the weakest of the Spanish factions, being made up of civilian volunteers. You also effectively stand alone against the entire world as you are playing as an aggressively expansionist political movement that has zero respect for the laws of nations, so the Allies, Axis and Comintern will all try to crush you unless they are all occupied in their own wars. But, a lot of rules and mechanics dictating how nations function in this game no longer apply to you — the anarchists can topple Portugal and later other countries to form the Global Defence Council, allowing them to effectively core and conquer the entire world in self-defence.
• Disc-One Nuke:
  • In Hearts of Iron 3, there is a stat which keeps track of what percentage of your army is made up of officers, and this directly affects how well your units perform (training more officers means your men are led better in battle). Keeping it up to at least 100% is necessary to have your troops in good shape, but it can be boosted up to 200%. This means all of your military will be at double their normal organization. And since the highest the AI will raise their officer ratio is about to 120% or 130%, it's fairly easy to steamroll over everyone else just by taking advantage of this stat, at least in the early game. Multiplayer games tend to have a 'house rule' of only raising the officer ratio to 120% or so, while later in the series the producers took steps to tone down the effect.
  • In Hearts of Iron 4, Great Britain's military is severely underprepared early on, France, Germany, and Italy can all easily navally invade and capitulate them quickly before 1939. This gives you all of their overseas territories as well as India and Malaya, and if you play your cards right you can also get your hands on the Commonwealth nations. If you turn them into a puppet, you get access to the Royal Navy and Air Force as well.
    • Similarly, Japan can serve as this for the United States and (with some build-up) Soviet Union - due to the AI being terrible at defending the home islands, if the US or USSR manage to get air superiority over the Home Islands or naval superiority over the Sea of Japan, it's very easy for either to take them out (since the AI will prioritize China on historical, leaving the home islands lightly defended).
    • France can serve as this for Germany and Italy moreso than the UK - not only does taking out France give Germany access to the French navy if puppeted and then annexed using the puppet system, but also makes forming any of Germany's formable nations much easier^note all of Germany's formable nations - the European Union, the Greater German Reich, and the Holy Roman Empire - require at least a few states from France; the EU requires all of France, the GGR requires control of Paris in addition to France having capitulated, and the HRE requires Alsace-Lorraine and Savoy, and as for Italy, it can be cored in both of the European Union and Roman Empire.
  • A general strategy for most fascist nations in IV is to join the Axis and attack the Netherlands early on - doing this will grant them access to the Dutch East Indies, which has a large amount of oil and rubber, the two resources everyone lacks.
  • An odd case for the Soviets: One of the best opening moves for them is to justify on Turkey as soon as they have enough political power. Doing so will not only drag in Romania without getting the Allies involved (thus allowing the Soviets to limit their fight with the Axis to one front), but will also grant the player valuable army experience, which is in short supply for the Soviets due to one of their starting spirits, pretty much grants the player a monopoly over Chromium if Turkey is made a puppet, and also frees the Soviet navy that's otherwise trapped in the Black Sea.
• Divided States of America:
  • It's quite possible, if the Random Number God is unkind to them in regards to random events or if they handle the aftermath of the Great Depression especially poorly, for regions of the United States to start organizing partisan militias and declaring themselves independent, eventually resulting in either the complete collapse of the country or a Communist revolution.
  • While the first game and HoI2 only involve the CSA, Texas and California seceding, one of the expansions, Iron Cross, takes it to a new level and adds Alaska, Hawaii, an Indian nation, Deseret, Chicago, New England, the Intermountain Federation, the African-American nation of New Afrika, and Cascadia.
• Double Standard: Bizarrely, while the Rape of Nanking is an in-game event (though outside of the Japanese player's direct control) things such as The Gulag, terror bombing, or the Holocaust are officially banned. The USSR does have the choice of enacting the Great Purge though. The game gives a severe penalty if you don't do it.
• Early Game Hell: With the two starting dates being 1936 and 1939, countries that were historically just about to get invaded and defeated are this. In 1936 China and Ethiopia are the two nations most prone to being attacked. In 1939 it's Poland & China with France and the other European nations bordering Germany following shortly after.
  • The inversions are the non-Democratic nations with the capability for early war declarations in the 1936 start, of which Germany and the Soviets are the best.
    • An early game tactic for Soviet players is to invade Turkey, Iran or Finland and possibly Sinkiang or Afghanistan in order to capture land, factories and more importantly enough Army XP to sort out their military unit templates and possibly gain enough to XP boost a doctrine tech. In the case of Turkey, doing so will also drag in Romania in later versions of the game, which can allow them to puppet Romania or Moldova and lock the Axis out of attacking from the South.
    • Germany requires oil, making a quick invasion of Holland to puppet the Dutch East Indies the most common opening tactic especially in earlier versions of the game. You could then refuse to bring them into the eventual World War, leaving you only to worry about getting the convoys past the Allied navy in the Pacific.
    • At higher difficulties playing the Soviet Union begins as an early game hell and extends that into the 1940 as you have to juggle your factory construction, putting up fortifications to stop the German attacks in some areas at least, and building up enough of an army that you eventually grind the inevitably German attack to a halt.
  • The United States has its own version of early game hell, because it's incredibly boring to play them in a historically accurate manner because they are very isolated, the country is wracked by the Great Depression, you can't invade anyone, it's slow to build anything, your army and air force is pathetic compared to the other great powers. The best chance to throw off these shackles is to prepare an invasion of Japan for when the "Panay Incident" event fires, declare war on Japan and immediately break out of the "Undisturbed Isolation" mobilisation level.
• Easy Logistics: Averted. All units consume "supplies" that needs to be transported to the front. Getting cut off from supplies is a VERY bad thing. Also, motorised units require fuel as well as supplies. Running out of fuel? Well, better build something other than tanks...
  • In II, not only your units require supplies and oil to run, but you also had to provide them to the frontlines first, using a crude, but still important Transport Capacity - twice your Industrial Capacity plus technological modifier. Going above it? Tough luck, because your entire army, navy and air force will start to suffer from logistical issues, shortages of supplies or total lack of oil, since your logistics simply can't keep up with the size of your forces.
  • III is often cited as the toughest game due to the extensive logistical system it uses. Everything from II stuck, but many elements were further expanded on. To move supplies, it costs supplies to simply keep the system running. Fuel got introduced, so you first need to refine your oil (or turn coal into oil and refine that), which required both industrial base to make it efficient. Infrastructure started to play much bigger role in transport capacity of your country (and conquered territories). On top of that, various technologies affected how much supplies could be moved and how much was needed to keep them moving. Ports were also needed to supply troops overseas and their level was a great choke-point on amount of supplies that could be delivered, easily stalling any invading force. If this all wasn't enough, bombardment of provinces and destruction of infrastructure played significant role in everything, along with those pesky resistance movements (not to mention actual partisans divisions). Did we mention there are also weather, climate and terrain modifiers? All in all, this made logistics a true nightmare for your army, because all the fancy toys could only do this much if you decided to deploy them in some backwater with a single dirt road to provide provisions.
    • From Semper Fi onward, III gives you a choice. You can use the 'realistic' supply system, which features convoys, air-drops, and is based on an engine that calculates the efficiency of your logistics system by how far from your nation's capital your troops are to simulate the logistics... or you can use 'arcade mode'. In arcade mode, you troops receive supplies no matter where they are, and as long as you don't run out of them you're fine.
    • One critical but often underappreciated feature of the logistics system in III is the role of La Résistance, represented by "revolt risk." There may be no armed rebels actively fighting against your army, but there is passive resistance sabotaging your supply system. Germany is, true to history, particularly heavily affected by this. You can have piles of supplies in your capital, but your troops in Torun, just stone's throw away from Berlin, are running out of supplies because of popular resistance. One way to re-open up the supply lines is to deploy regiments of "military police," which are really State Sec repressing unhappy locals and are good for absolutely nothing else (they have such ridiculously low combat value that they would flee instantly even in fights against rebels most of the time).
  • Zig-Zagged in IV. The logistical system has been completely revamped so that players must manufacture all individual equipment needed for their army, including infantry weapons, support equipment, artillery pieces, to even individual tanks and airplanes. In addition, changing an assembly line resets the efficiency. For instance, if the player changes a line manufacturing artillery at 90% efficiency to manufacturing anti-air guns, it will reset to 10% due to the factories having to start again. On the other hand, troops no longer need fuel and supplies other than replacement weapons when already fielded. It's impossible to actually be out of supplies or gas, making combat and army operation much easier to perform than in any of the previous installments, resembling 'arcade mode' from III. However, the expansion Man The Guns reintroduces fuel as a resource, with it being used to supply armor, airplanes, and ships. And despite those complex production elements, the logistics themselves are very simple, since everything is directly fed to your units whenever they aren't encircled.
    • Barbarossa and No Step Back massively increased complexity. Now you need to worry about how supplies flow down rail lines, keeping trains on those rail lines, those rail lines being bombed, converting the gauge of enemy rail lines, on top of making sure supplies can get from your rails and supply hubs to your troops, like how many trucks to assign to a given supply hub, whether your industry and fuel can support them, and so on.
  • Nukes are a straight example throughout the series. They're treated as an abstract resource produced by the nuclear reactors instead of an object with a physical location on the world map. Once you have nukes, strategic bombers in range of the state you want to drop a nuke on (or strategic rockets in II and III), and benefit from air superiority in said area (in IV), a nuclear drop can be ordered and executed almost immediately, regardless of the distance and supply lines between the nuclear reactors and the airfield the nuclear bomber takes off from.
• Easy-Mode Mockery: Playing below the 'Regular' difficulty (=normal) disables achievements.
• Elite Mooks: Mountain, paratrooper, and marine divisions are specialist infantry divisions, and have a slightly stronger offense than their regular infantry counterparts on top of their special terrain bonuses or abilities.
  • Their Finest Hour adds special elite infantry units for each of the major powers, i.e. Army Rangers for the USA, Guards for the Soviet Union, Gurkhas for the UK, and so on. They are notably more powerful than regular infantry or special forces for each country, and depending on the unit get certain bonuses, i.e. Rangers get an attack and movement bonus in woods.
  • Patch 1.7 of Hearts of Iron IV adds a limit to them to prevent players from using special forces in the place of all their regular infantry to create an entire Elite Army - by default, any given country can have no more than the larger of 24 battalions or 5% of their fielded battalions be special forces. National focuses and technology can increase this, giving a greater special forces ratio and reducing their training time or technology can instead double down on how elite they are, increasing their training time, defense, and organization. Additionally, it adds accimatization for units, which reduces their penalties in extreme heat or cold as they spend time in that climate, and special forces technology makes them acclimate faster than normal units (much faster on the quality route and only moderately faster on the quantity route).
  • In addition to the special forces ratio limit added in Patch 1.7 of IV, the accompanying Man the Guns DLC also adds amphibious tractors (essentially amphibious mechanized) and amphibious tanks. They use the same special forces cap as the infantry special forces and are mechanized and armored counterparts of standard marines. Additionally, they have very high fuel use and amphibious tanks are generally inferior to conventional tanks outside of their special niche of helping establish a beachhead or break through fortified marshes and rivers.
  • Arms Against Tyranny further retooled the importance of Special Forces by giving them doctrinal improvements and putting a larger emphasis on terrain disadvantages, meaning Mountain Infantry could potentially be the only thing allowing you to break that pivotal Alpine front.
• The Empire: Without heavy player intervention, Germany tends to explode out of its borders and overrun the majority of Europe by 1941 and keep it overran for years until the Allies and Comintern force them back (though if Germany wins the war in the eastern front the Allies are in for a bad time). Japan is also quite capable of overrunning much of Asia (and rather ahistorically tends to win the conquest of India due to Britain's generally lackluster efforts put into defending it) and forming one of these for a good while before they are thrown back. Italy tends not to have so much luck.
• Enemy Mine:
  • Due to the way how blocks (and in IV, factions) work, if you are fighting a war against a block and in the same time declare war on neutral country, the neutral side will join the block you were fighting with already. This can lead to such situations as Communist China joining Japan in war against China, or Romania jumping into Allies if attacked by any of the fascist countries. And in general, any neutral country will try to join any block it can during a war, which is the main reason why Allies start to rapidly grow in numbers once WW2 starts for good.
  • In IV, the Chinese Unified Front, should it be created, is about this: the central government, warlord cliques and communists stop fighting each other and instead fight together against Japan. Alternatively, if the central government goes for warlord subjugation early on, it can reduce them to puppet governments and then command their armies into the war, despite still being embittered political enemies caught in internal strife.
• Eternal Equinox:
  • Day and night do vary with latitude, so days are shorter in the Northern Hemisphere. But they're always shorter in the North — apparently, it's always winter there.
  • Hearts of Iron IV averts this, however, as the duration of day and night at different latitudes varies over the year.
• Evil Versus Evil: Depending on the course of history, it's entirely possible for the game to end in a final showdown between an alliance of fascist dictatorships and their conquered puppet states and an alliance of equally repressive Stalinist dictatorships and their puppet states. Or a final showdown between Germany, Italy and Japan when they're the only ones standing at the end.
• Fan Sequel: Arsenal of Democracy, Iron Cross, and Darkest Hour are all derivatives of the second game and use its game engine, and Paradox Interactive publishes them, but each is developed and maintained by an independent team consisting of fans of the original series rather than Paradox's own in-house developers.
• Fictional Flag: The game centers around managing countries in WW2 setting, as such, each country uses their real historical flag. However, if the country changes regimes (such as monarchic, communist or fascist), their flag will change as well to either real flags or completely fictional ones.
• Foregone Conclusion: Various historical events, along with WW2 itself, will happen each and every time, across all the games in the series. In case of II and especially in Darkest Hour it also means certain events will play out despite player intervention: Spanish Civil War will still happen (despite having three extra years of preparation and in theory ability to act against future Nationalist's commanders), 4th encirclement of the Jiangxi Soviet will fail (even if you micromanage it enough to completely over-run them and wipe out all troops), Tianjin Garrison can't be disbanded (and so it will get Japan into 2nd Sino-Japanese War) etc. II most infamously had a hard-coded event for admiral Isoroku Yamamoto to be shot down with his plane on April 18, 1943, with absolutely nothing to prevent that.
• Forever War: Disturbingly easy to make happen in II. While the War in Europe, Africa, and (possibly) the Middle East generally ends before the 40s are out no matter how many extra nations you throw into the Axis (Spain generally ends up being a bridge into Axis Europe as Franco can't quite cut the mustard against Gibraltar without help, while adding Axis Sweden tends to lead to Red Scandinavia, and Axis middle eastern powers usually fall to the Soviets or British soon) as the Allies and Communists usually beat the Germans and mop up the Axis minors, the war in Asia can go on for much longer if the AI decides it'd rather not do naval invasions today, and in the case of a South American Axis the Allies seem to have trouble pushing past a blockade above the Isthmus of Panama. The fact that the AI in II generally refuses to surrender without being occupied entirely or through event flags is a large factor in this.
• Game Mod: Countless, including ones which take the game to an Alternate History, World War I, The Vietnam War or Turn of the Millennium setting. A Cold War mod is presently in development. Also there is a Fallout mod. Some of these mods have/are being released as stand-along games, such as Arsenal of Democracy, and Darkest Hour.
• Gameplay and Story Segregation: In IV, when playing as Communist China, the Xi'an Incident event^note two of Chiang Kai-shek subordonates detained him to force him into agreeing for a ceasefire with Mao Zedong in order to make an alliance to fight against the Japanese threat allows to choose to execute Chiang despite Stalin's orders to agree for the alliance, and the ensuing flavour text states that Stalin is absolutely infuriated by this decision. In actual gameplay, it does no have any effect on the USSR-Communist China relation meter.
  • If Yugoslavia joins the Axis, the UK has the option of having the Yugoslavian military coup Prince Paul and install Prince Peter as leader, which in turn grants Germany a war goal. While this makes sense if Yugoslavia is independent and does so (which is what happens on historical), this can happen if Yugoslavia joins involuntarily as a puppet of another nation, or due to Germany or Italy declaring war on another country (i.e., Austria-Hungary or Greece) fighting Yugoslavia, which due to how faction mechanics work, will cause Yugoslavia to join the Axis. Curiously, this won't happen if Serbia is the subject instead, despite the Yugoslavian royal family being Serbian.
  • If Austria and Germany are both in the same faction, and are both Democratic or non-aligned, Germany can get an event that allows them to peacefully annex Austria, which will have Germany core Austria if the event is successful. While this makes sense if both countries are independent or Austria is a puppet of Germany, it can also happen if both countries are puppets, and also can happen if the Austria that exists is one liberated in South Tyrol^note which Germany won't gain cores on if it does the Anschluss focus or the event normally, and in the latter case, can happen even if Germany already annexed Austria through this event.
  • If the player opts to overthrow Stalin, the AI will have Stalin ensure the loyalty of random generals, which means that they will remain with him in the event a civil war breaks out - in-game, this is reflected by them gaining the "Stalinist" Trait, which can be prevented by having them gain another trait (Trotskyist/Bukharinist/Monarchist Sympathies, for Trotsky, Bukharin, and the Whites, respectively). However, a general gaining the "Stalinist" Trait can still be purged in specific events, meaning that it's entirely possible for Stalin to purge Mikhail Tukhachevsky after having ensured his loyalty.
  • One decision that was added for postwar flavor was the ability to form NATO, which is available to all of the founding members. However, the decision only checks the country, and doesn't take into account the ideology (or, for that matter, what faction the player is a part of), meaning it's entirely possible for a Fascist Italy to form the NATO while part of the Greater East Asian Co-Prosperity Sphere, a Monarchist United Kingdom to form it while part of the Axis, or most amusingly, for a Communist United States to form the faction while part of the Comintern.
• The Generalissimo: Comes in two flavours. One is a relatively common minister traits, "Resigned Generalissimo", making them better at providing army with supplies, but the public hates them, forcing an extensive spending on civilian goods, while the money from your industry is mysteriously vanishing... somewhere. The other is character-specific trait for certain historical leaders, making them actually awful at the job of leading the nation's military.
  • Accept no substitute when it comes to in-game leaders. Chiang always starts with this trait, regardless which part of the series you're playing.
  • Mexico in IV to deal with a revolving door of these, including Plutarco Calles, the former dictator and current shadow president, and Saturnino Cedillo, military governor and warlord of San Potosi. If you ally with the Gold Shirts, one of them can even come to power. President Lazaro Cardenas himself is one who's trying to become an honest politician and reform the system, though even he can succumb to the lure of dictatorship.
• Geo Effects: Terrain has a dramatic effect on combat; harsh terrain types like mountains, jungles, deserts, and any arctic environment impose penalties on attackers and defenders (but more severe for attackers) as well as doing attrition damage to the strength of whoever's invading. Rivers also impede progress and impose a penalty to attackers. Armor and artillery suffer the worst, while infantry suffer the least. Special forces divisions like mountain units (for mountain, arctic, and hilly terrain) or marines (for jungles, marshes, and rivers) actually get bonuses when attacking or defending in these areas, and engineer divisions greatly reduce penalties for harsh terrain. Certain technologies can reduce attrition in these areas as well.
• Gideon Ploy: In IV, The La Resistance Downloadable Content added the ability to create mock divisions of troops as part of its espionage mechanics, reflecting Real Life.
• Glorious Leader: Plutarco Calles, who starts as The Man Behind the Man in Mexico, is also known as "Jefe Maximo" (Maximum Leader). He came to power through the musical chairs of the Revolution, and while he's officially retired as of the game start, he still wields significant influence, and can retake open power by allying with the Gold Shirt fascist paramilitaries.
• Golden Mean Fallacy: II and Darkest Hour have internal political sliders. Going to either extreme end of each slider provides additional bonuses (and penalties) in specific fields. Staying in the middle does nothing at best and applies only penalties at worst - and yet it's a common rookie mistake.
• Harder Than Hard: The Elite difficulty, which grants the AI bonus modifiers that are anything but fair.
• Heavily Armored Mook: Consistently, this is how armor and mechanized or otherwise combined arms operate on the battlefield. Armored vehicles have a much higher Hardness and Breakthrough rating than regular leg infantry, which means that they're great for punching through enemy lines without taking significant losses but aren't so adept at holding a position from attackers. Ideally, armor works best as a backbone to a healthy and plentiful infantry which can reinforce the armor after it surges forward and gains ground in order to prevent territory from being immediately lost. Also, in II and Darkest Hours, heavy tanks and armoured cars exist only as brigades attached to your divisions, offering infantry and cavalry divisions predominately with Hardness and Defensive value, making the whole division more survivable in combat.
• Historical Villain Upgrade: Kenneth Althaus – in real life he was a very obscure U. S. Army tank commander with no ties to Fascist or Nazi groups. In II and III he is a National Socialist chief of army minister if the US slider goes right/authoritarian enough. It led to a complaint from a grandson.
  • Also in II, a man by the name of H. R. Mengert can become a Paternal Autocrat U. S. head of government. The real Herbert Reinhard Mengert (1886–1950) was a perfectly ordinary newspaper correspondent for The Cincinnati Enquirer in Ohio, with nothing to suggest he had sympathies for authoritarian rule in America.
  • Douglas MacArthur in IV can lead a revived Confederate States of America. Historically, MacArthur was close to his father, Arthur MacArthur Jr, who was a decorated Union officer in the American Civil War. Sufficient to say it's pretty unlikely that he would choose to lead a government that stands for everything his father fought against.
  • Another potential leader for the revived CSA is a 1936 presidential candidate Alf Landon, who is portrayed as a Fascist for some reason. Landon not only supported many of the goals of the New Deal, he actually fought the pro-fascist groups that wished America to not fight Nazi Germany in WWII.
• Hitler's Time Travel Exemption Act:
  • Because the game mechanics of the series revolve around preparing and fighting for a major global war, this is in full effect. Even in the cases where Germany or Japan doesn't kick the war off, the British or Soviets will.
  • HOI4 (with Waking the Tiger) added a somewhat downplayed example not directly tied to starting a war: if Germany goes for overthrowing Hitler, France switches its focus tree AI for one that is set to never take the historical democratic political path^note unless you have the AI set to follow historical focuses, France's AI is also set to not make their choice until Germany has made theirs, so a German player can't bypass the issue by simply waiting until France has already started on their democratic path, instead becoming either Fascist or Communist^note the gameplay reason for it is to avoid making things too easy for the German player (since overthrowing Hitler lessens tensions with the Allies) by ensuring France will be hostile, if not necessarily an active combatant against you, unless the player opts to restore the Central Powers^note as this will still bring Germany into conflict with the Allies.
• Hold the Line: A handful of countries have to pull this for their immediate survival, be it China, Poland, Finland, France, or eventually the Soviet Union, to say nothing about minors like Belgium or Denmark. Depending on the part of the game, this might vary from a near-impossible task to a relatively easy affair. Notably, from II onward, the game contains various additional safeguards (bonuses, debuffs, extra fortifications, etc.) to at least make the historical cases of holding the line possible, even against all odds, so the AI can pull it, too.
• Hollywood Tactics: Can be used by the player or the AI, though generally not advisable, unless you have a serious numerical advantage. Surrounding and cutting off the enemy is a good strategy, however, because it cuts them off from supplies; it's also the easiest way to take out a brigade for good, rather than just allowing them to retreat and get reinforcements.
• The Hunter Becomes the Hunted: In early game, submarines can operate with almost total impunity, with most of doctrines for them being ready around '40. But around '41 mark, a lot of radar technologies, new destroyer models and anti-submarine warfare doctrines are no longer penalised for research, quickly turning the table and making life for subs hard. By '43, submarines are virtually useless, as even AI controlled nations will easily hunt them down.
• Hypercompetent Sidekick: The Silent Workhorse minister trait is basically this.
• In Spite of a Nail:
  • Most often seen when importing in a scenario from Victoria: An Empire Under The Sun. Whilst the borders and existing countries will change, the leaders most often won't. Meaning that you can have Adolf Hitler in charge of a democratic Germany, with or without World War I having happened.
  • Tech teams and leaders in II are hard-coded. This means two things: you are stuck with whatever is pre-defined for your country without any ability to upgrade or switch^note Eventually, an option to capture tech teams of conquered nations was added to alleviate the issue somewhat and, much worse, they are removed from the scenario either by event^note some at least do have specific triggers, but most do not or expiration year, regardless of whether the circumstances in the leader/team became unusable in real life are in place or not.
  • Great Britain is hardcoded to always declare war to Germany in the 1940's, no matter what is the geopolitical situation. Even if you managed to play Germany as a democratic state with peaceful relations with Poland and the Western Europe.
  • In IV, there's a chance that someone will spot the problem that would have caused the Hindenburg disaster, resulting in it safely reaching the its destination. However, it's stated that the public's trust in airship travel is still shattered due to how close it came to disaster, since the problem^note While the game does outright say what caused the disaster, in real life the cause is unknown to this very day, with several different theories floating around was only discovered by a stroke of luck.
• Interface Spoiler: When choosing ministers and army staff as Soviet Union in IV, finding out who can be victim of the purges is obvious from the very beginning of the campaign, as the conditions for hiring most of the advisers and generals includes "Not: Purged by Stalin" or "Not: Purged by Trotsky".
• Irony:
  • Not only the wide-open sandbox gameplay technically allows to invade China while playing Tibet, but the game actually incites Tibet player to do so^note to reclaim the Xikang state, a South-Western China province bordering Tibet at the start of the campaign (it's a former Tibetan territory lost to China a few years earlier)
  • One of IV loading screen shows Churchill and a group of British officers looking at a map. It's based on a real photograph, except the original featured German personnel (Churchill replaces Goering, and the moustached officer sitting in the middle of the photograph is Hitler in the original picture).
  • According to this, many generic generals/amirals portraits are based on photographs of real people, not necessarily from the right countries... and sometimes from the other side. For instance, four of the Japanese generals are made from photographs of Chinese people (including Chiang Kai-shek's son), and three of the Italian generals were in the allied side during World War II (one of them is based on the US Marine John Basilone, who was born in USA but was of Italian descent). At least one minor country has Captain Mainwaring as a senior officer.
• It Only Works Once: In IV, one of the decisions is to reorganise your railway system, offering a massive discount on the construction of new supply depots. The catch is that you can't have more than 49 factories, can only ever enact it once and on top of that, it will deactivate on its own after building three depots. Didn't manage to squeeze the full potential of the bonus? Got the 50th factory? Too bad, you will never get that decision again.
• Jack of All Trades: Tactical Bombers do a little of everything close air support, strategic bombers, and naval bombers do, but not as well as any of the more specialized air units. While they make expensive substitutes for CAS and NAV planes, their range may make them worthwhile over large or deep sea air zones.
• Joke Character:
  • In HoI4, several of the Chinese minor factions (Shanxi, Yunnan, Xibei San Ma, Guangxi Clique) are basically unplayable because a scripted event merges them into Chiang Kai-shek's China once Japan starts invading mainland China (end of 1937). They become functional countries if you play with the Waking the Tiger DLC, though.
  • Waking the Tiger allows the current "main" faction in China to eventually get American support in form of General Stilwell. He is skill 1 general with lackluster traits, while even the least competent Chinese ones start at skill 2, on 1-9 scale. The fact he's very low in the focus tree makes it even worse, because due to fighting defensive war against Japanese for past few years, Chinese commanders will be even better by the time Stilwell is unlocked. On the flipside, it's also possible for them to get Douglas MacArthur or Dwight D Eisenhower from the same focus, depending on what the Americans respond with, but default option is Stilwell.
  • Tannu Tuva. A tiny nation located in Southern Siberia that starts in the Comintern. The Soviet Union has a focus tree to annex it, as they did historically in 1944. Being the game it is, you can still do world conquests at least in HoI4, it just takes a lot of luck and skill because you have no manpower, awful technology and the spectre of the Soviet annexation looming. You basically have to invade Sinkiang, Tibet, Nepal and then take Xibei San Ma then the People's Republic of China with all of these problems so that you will have the manpower & factories to resist the Soviets when they come wanting to annex you.
    • The fictional scenario in HoI2 has Tannu Tuva for some reason being the only nation with exactly one province that is not allied with any other superpower.
  • Luxembourg. A single province, a low amount of starting industry (1 military factory and 3 civilian factories) and no room for expansion, a pathetic starting manpower, no starting army, and their initial army template is a joke (a single battalion supposed to serve as a police force)... and Germany will invade them to bypass Maginot Line.^note Luxembourg is initially democratic. The easiest way to survive the game as Luxembourg is to convert to fascism and join the Axis.
  • Albania: You are economically dependent on a country which has every intent of annexing you (Italy) and have very little industry. As with Luxembourg, your only real hope for survival is to convert to Fascism and join the Axis.
  • New Zealand: While you start off in the Allies and thus are protected by the UK and her colonies, your limited industry and manpower means that you’re basically screwed if Japan invades you, regardless of whether you have taken advantage of the country’s good tank research bonus focuses.
  • Mengkukuo. The weakest industry in the game, with one civilian factory and no military factories. Good luck getting literally anything done without the help of your Japanese overlord.
• Leitmotif: Each faction, most recognisably the Comintern, gets its own theme in the third installment. The themes get retooled depending on how each faction is doing; if they're winning it's loud and triumphant, if they're losing it's quiet and subdued.
• Legally Ousted Leader: While there are several country-specific Alternate History routes that exemplify this trope, all countries have the option of passing a referendum to put a different political party in power.
• Magikarp Power:
  • Nationalist China has this going for them from the start. Rare materials, industrial capacity and tech are lacking from the start, and China's general region is divided into many warlords and some opposing factions, with Japan is peeking at them from a distance and Communist China threatening to backstab them. Should they survive the first couple of years and push back against the factions and especially Communist China, as well as building up a strong enough army to deal out serious blows against both, China becomes a solid major power capable of world conquest. And if China becomes democratic, it can become one of the most powerful members of the Allies after the Chinese Civil War is finished.
    • In Hearts of Iron II this goes even further. If China successfully push Japan off the Korean peninsula, they can receive the "Setting Sun" event which forces Japan to hand Korea over to China; due to how the game mechanics work, Korea inherits all the technology Japan had at that point and offer free blueprints as they are a puppet nation to China. The same event also provides China with new, upgraded tech teams. This allows to catch up tech gap at very quick rate.
  • In II and Darkest Hour, cavalry is basically outdated and outperformed by pretty much anything it can meet, as contemporary units will be always stronger, better armed and armored. When cavalry gains few trucks, a purposefully build motorised infantry is already present. Cavalry gets halftracks? There is mechanized infantry already for few years. And then after a series of semi-related secret tech research, you unlock air cavalry. Your cavalry scraps most of its land vehicles and is outfitted with choppers instead, turning into blitzing fast unit that packs a serious punch, is cheap on both manpower and IC (just like all other versions of cavalry) and basically outperforms most of contemporary units even if they carry support battalion or two. Also, air cavalry still count as land unit, so you don't suffer air drop penalties nor have to deal with enemy interceptors and fighters. In case of finding hole in enemy lines, you can outrun half of the country until you run out of fuel or get encirclement. And due to their speed, air cavalry units are almost tailor-made for quick, swift encirclements, allowing to wipe out entire divisions caught in the pocket and cut entire armies out of supply.
  • In IV, the Anarchist faction in the Spanish Civil War has the weakest military and the issue that nobody will want to ally with them. However if they manage to come out on top and then later form the Iberian Defence Council (and eventually the Global Defence Council), you have a faction that ignores many of the core rules on how to rule and expand a nation. For instance, no more coring - the Anarchists can core any territory in the game simply by taking it over.
  • IV has this for light tanks combined with Not Completely Useless in late game. Light tanks are tin-can popgun go-karts compared to medium or modern tanks, and are absolutely crushed by heavy tanks made even less useful in No Step Back update as their armor is more and more penetrable by a few upgrades. But as technology marches on, mid-game engineering research can have them be fitted with a flamethrowers, armor skirts and dozerblades and turned into a very specific support unit with murderous levels of combat bonuses to a division up to 40% in urban terrain, turning run-of-the-mill garrison material 18 width infantry squads into armored Elite Mooks with just a few cheap tiny tanks which can be produced faster than pizza by the time flamethrowers are developed. Better yet, old captured light tanks and former older tanks can be retrofitted as well, making excellent efficient use of junk materiel.
    • Again for the fourth game, motorized rocket launchers (and towed ones as well). In early game, rubber is limited to Asia and Africa, and earliest models are simply not worth it. However as synthetic rubber production shoots up, rocket motors and stabilizers are added, the motorized trucks with rocket launchers become murder on wheels: for a tiny bit of steel and rubber(which can be synthetized while tungsten and steel are limited on Earth), they consume less steel than towed rocket artillery and less steel *and* tungsten than towed artillery, (which also need more trucks to pull the damn thing to the front) while maintaining the mobility (thus the greater breakthrough value) and enjoy better firepower at maximum rocket technology level. The downside is they cannot be support companies; but as line brigades, they can turn human waves into mincemeat and at highest level can destroy tanks as well without taking a scratch. A division with tube artillery support company, motorized rocket artillery as line artillery can dish out insane levels of soft attack while its humble infantry can give the organization it needs to stay on the field. A tank division with cheap, easily replaceable motorized rocket artillery (opposed to SPAG) can become a whirlwind of destruction.
  • DLCs from IV are quite infamous due to their inherit Power Creep, but two countries with DLC-granted focus trees stand out the most when it comes to Magikarp status. AI is scripted to not do them, and they seem like a Violation of Common Sense for human player, but still:
    • Normally, Yugoslavia is your average minor with some extra aluminium that can think about becoming a regional power. With Death or Dishonor, Yugoslavia can self-balkanize, which, contrary to what it looks like, makes it way, way stronger than a unified state. Each of the split-off countries remains the puppet of the central, while having access to the generic focus tree, each roughly corresponding to a single state. That in turn means each of those states gets full benefit from the economic part of the focus tree (maxed out infrastructure, 4 civilian and 3 military factories - with free slots for those - and maybe also level 2 airport). Normally that's barely noticeable... but Yugoslavia can release staggering nine puppets that can be then simply integrated back. That's potential for up to 36 civilian and 27 military factories in max infrastructure states. For some perspective - that's more than the starting industry of Germany. And both Yugoslavia and its puppets can obviously expand in the meantime. Most importanty, however, Yugoslavia can achieve all of this by late 1938, maybe early 1939 if the AI picks the "wrong" focuses for puppets.
    • Ethiopia under By Blood Alone can go through a near identical situation, except it also gains free resources and only when going for the Balkanize Me focuses. The resulting country is insanely powerful due to the size of its industrial base and doesn't need to trade for resources with the outside world, having zero problems with world conquest or fulfilling its seemingly tough achievements (conquering Egypt, Palestine and large sections of East Africa). At the game's start, Ethiopia is semi-tribal country with barely any industry or technology and is already fighting a war against Italy, being overrun under AI control in less than 2 months.
• The Man Behind the Man: Any Head of Government ministers with good traits are this, especially if the Head of State is a "Insignificant Layman" or "Popular Figurehead".
• Meaningful Rename: Every country in the game has a variation on their name that is chosen depending on whether they are Democratic, Communist, Fascist or Non-Aligned. Some nations can have multiple names within a single ideology, depending on the exact circumstances they made the change. There are also the formable nations, in which multiple nations are unified into a single new one with a new name, each of which also have their ideological variants.
• MegaCorp: The Military Industrial Organizations introduced in Arms Against Tyranny can eventually become this. As you, the Government, lease out research contracts and production licenses to these private companies, over time their funding will swell and they will increase in size, allowing you to allocate Trait Points which improve the equipment they build. The possible size goes beyond 10, but to get an Organization to that size will require you to be well into the late game.
• Mêlée à Trois:
  • Western Allies and Soviet Union sometimes go to war against each other while World War Two is still going, turning it into a Allies VS Comintern VS Axis conflict.
  • With La Résistance, Carlists and Catalonian anarchists can secede from Spanish Nationalists and Spanish Republicans respectively, turning the Spanish Civil War in a three-way conflict (or four-way if both spawned).
• Mexico Called; They Want Texas Back: The Mexican national focus tree gives them cores on their former territories.
• Min-Maxing: Many division bonuses from generals and ministers depend on what "type" a division is, which is automatically determined by the total weights of each unit type that makes it up, which leads to cases like balancing tube, rocket artillery, and even motorized or self-propelled artillery to keep a division an "infantry" division to retain bonuses while stacking as much soft attack as possible in the division.
• Mood Whiplash: In IV, if you own the extra music packs and the Allied Speeches DLC, then the radio will bounce back and forth between some of the most dramatic and dire speeches in history and easy listening jazz.
• Monumental Damage: In IV you get some morbidly descriptive text if certain cities are nuked:
  London: At (day), Big Ben chimed for the last time, having been melted by the blast. Early reports suggest Buckingham Palace has been completely leveled and the whereabouts of the royal family are currently unknown.
  Kyoto: The city's location in the valley somewhat limited the blast, but the old Imperial Palace and many industrial buildings have been completely destroyed.
  Tokyo: The capital of Tokyo, although expected to be the target of firebombing, was never assumed to be a prioritized target of this new weapon. Yet ultimately, perhaps due to the significance of the new capital and Imperial Palace which has now been destroyed, an even more all-consuming fire has fallen on the city.
  Washington D.C.: In an attack clearly directed at the political center and historical legacy of the US, the White House, the Capitol and a number of monuments and memorials were wiped off the face of the Earth. Even the Burning of Washington over a century ago pales in comparison to the destruction visited upon the city by this devastating weapon.
  Rome: Due to its historical and artistic treasures, many had never thought the ancient city would be the target of such indiscriminate destruction. With the Vatican City also partially destroyed and the whereabouts of the Pope unknown, the event has horrified not only Italians, but Catholics around the world.
  Paris: Any victory parades at Champs-Élysées past the remains of the Arc de Triomphe seem unlikely in the city's current state. Perhaps the coming decades will see the birth of a new Paris, but Paris in the public mind, the city built in the Belle Époque, is gone forever.
  Moscow: A city many have tried and failed to conquer, Moscow was the target of a nuclear attack today. The explosion was directed at the heart of (leader's) leadership, the Kremlin having been nearly completely destroyed by the blast.
• Moral Event Horizon: In-universe. The reaction of all the major powers' authorities to the Spanish Anarchists prevailing in the Civil War and then toppling Portugal and forming the Iberian Defence Council is basically "we need to crush this political movement that has no respect for the laws and customs of nations right now".
• Necessary Drawback: Throughout the series, after certain point in the tech tree, each and every unit will start to require fuel to operate. This keeps a balance against just about anyone who simply tries to tech-out, without securing oil or fuel production, while giving also a reason why not to keep advancing for better units to make your logistics easier, relying on blunt numbers rather than superior firepower.
• Nerf:
  • Naval bombers have a rather uniform history of being continously nerfed in each part of the game and with all major patches, often to the point of highly unrealistical restrictions. And yet they are still extremely efficient in their job and always considered the biggest threat to any navy within their range.
  • IV completely unintentionally nerfed carriers, from near-game-breaking to near-useless due to new air combat mechanics. Then the changes in naval combat from patch 1.6 made them a total waste of resources, production and research, for they became sitting ducks for other ships to pound, with no real means to retaliate.
  • Also in IV, any minor country that got its own national focus tree thanks to a DLC usually suffers from a significant nerf. The generic focus tree is nothing fancy, but it offers very upfront and easy to get benefits, significantly bolstering your starting position. Country-specific focus trees, meanwhile, tend to introduce a whole host of esoteric mini-games and usually provide less factories, less research bonuses and far less options to switch your government, spread over few times larger tree. Most prominent examples are the Chinese warlords^note Especially when compared with a Japanese puppet state of Mengkukuo, which gets thrice as many factories, massive infrastructure improvements and potential for enormous recruitment bonus before the Second Sino-Japanese War starts, while warlords will be given almost nothing from their focus trees, Baltic countries and Ethiopia, who all went from "drab, but decent" to "elaborate, but mostly useless".
  • Starting from II, each following game offered a worse and worse ability to share technology. II had blueprints, halving the time needed to research that specific tech and applying it first in the calculations, before any other modifier. III removed blueprints, but gave the ability to share Theoretical Knowledge in a specific field, offering a scaling modifier up to 39.5% boost to all techs related to that field (which meant a whole bunch of different research going along could gain the bonus). IV has a meaningless -5% research speed per member of a research group that already has that specific tech while only applying to new research, rather than affecting the ongoing ones - and there is just no way to pool efforts otherwise.
• New Meat: Replacements for killed soldiers decrease the experience value of the whole division. Take enough casualties and even that elite division of yours will turn into poorly trained fodder. In IV, this is especially painful when trying to replace navy loses - since you are now at war, there is no time to carefully train your crews to be familiar with their ships, leaving you with rookies and related penalties to performance.
• No Campaign for the Wicked: Averted. You can play any nation that existed or plausibly could have existed at the time of the game's scenarios apart from microstates like the Vatican or Monaco, including more obscure (with respect to WWII) nations such as Nicaragua or Liberia.
• No Points for Neutrality: Enforced in various ways:
  • By default, this is a game about taking your part in WW2 and doesn't provide almost any game mechanics for staying away from war, aside doing industrial build-up for it.
  • In II, political sliders provide special bonuses for final three steps in either direction, but staying around the center of each slider gives nothing of value and no speciality.
  • In III, non-aligned nations receive few small, but still nasty penalties. You either join any of the three big blocks (and thus the war itself, but also receive the block's bonus), or it will keep persisting. Fighting small wars on your own is generally a terrible idea.
  • In IV, non-aligned is a special type of political option, which, at least until La Resistance, was always a sub-par option. Non-aligned nations don't even benefit from the small bonuses democracies get, not to mention the boost totalitarian governments of either flavour enjoy to waging war or preparing to it. The game almost explicitly demands from a player to take a side and any non-aligned path usually means sitting and waiting with defense against invaders - which tends to be boring.
• No Swastikas: Averted by some user-made modifications, though discussion of them is generally penalized on the official forums and After-Action Report writers often pixelate them if they're using such a mod. Played straight in "vanilla" III (which uses the Imperial tricolor^note Nazi Germany did briefly allow the tricolor to be used in place of the swastika flag, but had already discontinued the practice by the game's earliest 1936 start date) and IV (which uses a variant of the war flag with the Iron Cross in place of the swastika).
  • Averted in Darkest Hour, where Germany actively switches the flag in 1933 start in one of the first decisions and in any later dates already has the swastika flag. However, the game started as a mere mod to II and was only later released as a separate thing. You're still required to censor it on the official Paradox forum.
• Non-Indicative Name: The "ideologies" of HOI4, as they were originally designed, represented factional alignment (Democratic = Allies, Fascist = Axis, Communist = Comintern) rather than the aesthetic-narrative indicators that many, many HOI4 mods have adopted. This resulted in a rather... screwed up situation as anarcho-communists in Spain gets called "Non-Aligned" (and previously even allowed Monarchist France to support them just because they are also Non-Aligned), the decidedly Italian-fascist-modeled Vaterländische Front in Austria getting called Non-Aligned because they opposed Germany, and anti-Soviet communists in Spain can join Stalin's Comintern just because they were ideologically Communist.
• Not the Intended Use:
  • Engineers in Darkest Hour are a defensive brigade that helps with digging out field work and to deal with certain terrain types, but is otherwise lackluster. However, their main use is to balance out movement penalty artillery brigades add, giving a well-rounded and still fast divisions with powerful artillery support that is particularly good at river crossing and overcoming fortified positions thanks to combination of firepower and engineer bonus.
  • Radars in III exist to bolster defense of your skies and helping your interceptors locate enemy planes. They are also the easiest and most reliable way of providing intel on enemy units, for they reveal position of all enemy units in their range (which is few hundred kilometres) in real time, even during peace time.
  • Armored cars in IV are intended as support for your division and mostly useful for recon and garrison duties. Instead, they work best as highly cost-efficient light tanks, particularly tier II, and create a solid duo with motorised infantry for infiltration divisions, as they travel at the same speed. For added cheapness, they require virtually no research, cost only steel and have good enough stats to fight against actual light tanks - or even easily take out medium ones by tier III.
• Nuke 'em: You can do this after some appropriately lengthy research. Using a nuke not only destroys large stacks of units, it also gives the targeted nation a major dissent hit. This causes their army to perform very weakly. In the third installment of the game, nuclear bombs also pretty much level the entire infrastructure of the target province (air bases, roads, factories, rocket test sites, and so on) with the ground.
• Obvious Rule Patch: All four games suffer from this to various degree. Each time when some unit type or specific tech is find too powerful, it instantly rebounds in next patch by being nerfed to the ground with quickly slapped together change of values and stats that make it so strong. This usually leads to emergence of something else as too powerful and the cycle starts again or at least complains about the extensive nerf rendering something utterly useless. Carriers and naval bombers are probably most notable for this in all four games, as they are always introduced as strong in release state of the game, then nerfed, then "fixed" to be useful again, then nerfed due to being too powerful, then buffed again...
• Off the Rails: In IV, when playing with the historical focus mode enabled, the AI managing the various major country will try to take focus which follow real history as closely as possible. If the player is fooling around in historical mode enabled and perform non-historical actions, the AI will still closely follow this line of action regardless if it makes sense or not, which can have weird results. For instance:
  • If the Western Allies crush Nazi Germany, they usually turn it into a weakened puppet with a democratic government and part of the Allies faction. If they manage to do it early enough, their democratic puppet will carry on its aggressive policy and eventually declare war on the Soviet Union, with the support of the Allies. This even if the puppeted democratic Germany has not trained any divisions to replace the army that was disbanded after the fall of their original government...
  • If Germany isn't able to get its territorial demands, either due to the country in question refusing and Germany being unable to declare war on them (i.e., if Poland joins the Comintern, and Germany being unable to make demands since Non-Aggression Pacts cover all faction members), or the country they would normally make demands from not existing (i.e., if Poland isn't around for them to demand Danzig from, due to Lithuania forming the Polish-Lithuanian Commonwealth), the game can change very drastically, ranging from Germany merely starting the war by attacking the Benelux to them instead outright attacking The Soviet Union first, thus allowing for the Soviets to remove the debuffs of the purge sooner.
  • Due to historical claims, several nations have claims/cores held by other states. If tension gets high enough early on, many non-Democratic states will start justifying to reclaim their cores/gain their claimed territory, even if the territory in question is held by a stronger nation (i.e., Lithuania has a core on Wilno, which is held by the much stronger Poland) or the holder is guaranteed by a major (for example, Greece has a claim on North Epirus, which is held by the Italian guaranteed Albania) - which can result in the weaker nation either getting annexed earlier or by someone who isn't normally supposed to. It can also result in World War 2 being kicked off by countries who didn't join until later on, such as Bulgaria attacking Romania over Dobrudja (drawing in Czechoslovakia and France, and having Romania join the Allies, with Bulgaria joining the Axis, and both countries calling in the other members of their factions), or having countries be unable to receive guarantees, such as Poland being attacked by Lithuania (the British AI will issue a guarantee to Poland as soon as Germany starts Danzig or War, but if Poland is at war, the UK will not be able to issue said guarantee).
  • If the Netherlands, Belgium, or Luxembourg goes communist and joins the Comintern, the Germans will be unable to attack them as long as the Molotov Ribbentrop pact is in effect...even if they control the entirety of the Benelux, thus meaning that the Germans and French will essentially be limited to fighting air battles. Strangely, despite the German focus tree having "Operation Tannenbaum", a focus that seems like it's designed to prevent this (said focus is based on their planned but never executed invasion of Switzerland), Germany will never attempt to bypass the line by going south and invading Switzerland.
  • Italy being denied victory in Ethiopia, even if Italy doesn't wind up overthrowing Mussolini, can have significant consequences for the country - as long as Ethiopia is still around, Italy can't get involved in the Spanish Civil War, and in addition, will not be able to make good on any of its Balkans ambitions, thus meaning you'll get stuff like Greece being on the offensive during the historic war the two had.
• Old Save Bonus: Paradox have a range of similar titles based on periods throughout history, and it's possible to start a game from 1066 (in Crusader Kings) or even 769 (in Crusader Kings II) through several other games (Europa Universalis and Victoria: An Empire Under The Sun) until Hearts of Iron ends the campaign in 1964. East Vs. West was supposed to cover the Cold War era but it was, unfortunately, cancelled.
• Paper-Thin Disguise:
  • One very specific and low-probability chain of events in IV (with Waking the Tiger and Man the Guns DLCs) can have German-American architect Adam Hilt coming to power as a fascist leader of America. Adam Hilt is actually just Adolf Hitler with his moustache shaved off.
  • Similarly, Señor Hilter of Argentina is just Hitler without his moustache wearing a hat and big shades.
  • La Résistance adds another two more disguises to the list should Germany be defeated. After a certain amount of time, one of the two agents named Achim Hund and Andrea Hund might become available to German players, which are clearly just Hitler with a bigger moustache and a monocle and fedora, and Hitler with his moustache shaved off trying to disguise himself as a woman, respectively.
  • Battle for the Bosporus adds an Adolfos I (a bald Hitler in purple robes, sporting a thick beard and wearing a laurel wreath), who can rise to power in fascist Greece if Hitler has been deposed in Germany.
• Paper Tiger:
  • At first glance, France looks like it could be a first-tier power. On second glance, it's second-tier. Actually, France is a third-tier power masquerading as a second-tier: it starts with useless generals, weak tech, fractious politics, and a hostile first-tier sitting right across the border. Your primary goal playing this nation isn't so much winning as avoiding being booted off the continent entirely.
  • Similarly to France, Italy has the distinction of being a "major" nation that barely even looks the part. No matter which game in the series is being analysed, Italy is a complete pushover in AI's hands and severely underpowered for a major even in the hands of a competent player. And it's also incredibly easy to mismanage it into being even weaker, particularly in Darkest Hour and IV. All there is to say is that Italy can't even reliably win the war against Ethiopia, a semi-tribal country with close to no military and hardware. Luckily, at least in IV it got a huge buff in By Blood Alone, although the player will seriously have to work their ass off to whip the country back into shape and then some if they want to, say, reform the Roman Empire.
  • Turkey may look powerful compared to the Balkan countries, but in reality, its air force and navy are even weaker than Greece. Due to this, it cannot attack Greece in any way other than through a deadly mountainous chokepoint. Greece can win the war simply by tiring the Turkish army out and counterattacking with its superior mountain infantry.
  • The United States is a very, very downplayed one, in the sense that they're not so much weak as not nearly as powerful as they should be on paper, due to a massive amount of National Ideas keeping their military power ham stringed, which can only be removed by certain Focuses. Its main saving grace is that because they're on the complete other side of the world from the rest of the Major Powers it is left to its own devices and free to build its military up more or less unmolested - though with its updated Focus Tree careless maneuvering can result in a Civil War breaking out.
• Point of Divergence: Even without your input, there is a certain chance that historical events will play out differently than they did in Real Life; for instance, the Hindenburg's gas leak is spotted and repaired in time (thus averting her fiery explosion), Amelia Earhart successfully touches down on Howland Island (instead of mysteriously disappearing on her way), and Leon Trotsky overpowers and kills his assassin with an icepick (instead of getting killed by a blow to the head). Some on these bring potential changes your gameplay options (enabling you to hire Earhart as an advisor, or as an ace pilot in IV, or initiating a resurgence of Trotskyism). In the case of the Hindenburg, the effect on gameplay ultimately depends on what ideology you pursue: if you stay fascist, not much will happen aside from Rudolf Hess possibly using the blimp for his famous flight (which only really translates into a different news event), but should one restore the Kaiserreich, on the other hand, it can allow for Germany to crown a Kaiserin, and eventually restore the Holy Roman Empire.
• Power Creep: The DLC system for IV has supplied ever-increasing power creep for whichever nation(s) get a new focus tree or tag-specific decisions. In fact, eventually major countries required an overhaul of their original focus trees to at least somehow match the resulting disparities - and then became outpaced by new focus trees anyway. Notable examples include, but aren't limited to things like:
  • Mexico, which was not even remotely a major participant in the war, becoming a Troskyite superpower that can take over the US.
  • Poland being able to reform the Polish-Lithuanian Commonwealth four different ways and become genuinely able to fend off Germany's invasion by late 1937.
  • Yugoslavia easily becoming more powerful than neighbouring Italy, while getting cores all over the Balkans, all by spring of 1938, about two years before Italy can even consider attacking it.
  • Ethiopia, a semi-tribal backwater that's already in the process of being conquered by Italy from the start, yet getting resources and industrial base of a major country by 1940 solely by focuses.
  • Portugal, another non-participant of the war, swallowing all of Iberia and regaining direct control over Brazil, their former colony - all of which can be done with a bit of planning just before WW2 starts and thus being able to join it as a major contributor.
  • Denmark, a nation hit extremely hard by the Great Depression and with an underfunded, almost symbolic military historically, being able to core all of Scandinavia, the Baltics and England^note Coring England and the Baltics are mutually exclusive, likely as an Obvious Rule Patch, potentially becoming a Space-Filling Empire to rival the Soviet Union in terms of manpower and industry.
• Power-Up Letdown: Intelligence agencies in general, and tech-stealing in particular from IV. For the time and factories invested in it, the results are just insulting. There are at least 3 different mods that simply slash the time needed for espionage missions to make them even remotely worthwhile. Oh, and to add insult to injury, to even get those questionable options, you need to buy a DLC first.
  • Intelligence agencies take a horrendous amount of time to set up to be fully useful and it's very easy to simply forget about adding new upgrades in the thick of it. Then they take just as long to build up a spy network in a very small region, which then allows them to execute missions that require first infiltrating enemy ranks and then performing another mission to do the thing you wanted to do^note And if you reload the game, the infiltration will be cancelled, forcing the player to start from scratch. It will take anywhere between 10 to 16 months, for just one mission in a single country. The game lasts for 10 years. Oh, and various missions require you to assign 3 spies to them, meaning you will also need to assign a political advisor offering +1 spy or have a few regional powers as your puppets.
  • Tech-stealing takes it a step further, since all of the above applies, but adds a few extra hurdles: you have very limited control over what is being stolen, so the bonus can get extremely niche^note Say you want to steal naval blueprints. The game then makes a roll and decides you get a bonus to the mine-laying technology or naval rangefinders, rather than general "cruiser technology" or "ship armament" groups, which at least can be used for a bunch of different things and, worst of all, unless highly specific circumstances are met, it's just a generic -10% research time. You've spent a year of elaborate missions that syphoned resources along the way to research a single technology 8-13 days faster. The only exception is when stealing from a country two tiers better in any given tech line (this will generate a 1-3 years of catch-up research bonus), but that means you are already lagging behind big time.
• Puppet State: Present in all four games, with the Communists being particularly fond of creating them. IV adds a tiered system of levels of dependence, ranging from a Dominion (like Australia or Canada) that's largely independent except in foreign policy, to a somewhat autonomous Colony (like The Raj), to a totally subservient Integrated Puppet (like Manchukuo). The tiers are indicated with chess pieces, from pawn to queen. Death or Dishonor adds a separate system for fascist nations, going (from least autonomous to most autonomous): Reichskommissariat -> Reichsprotectorate -> Satellite -> Independent. Waking the Tiger adds yet another separate system for Japan and (if it becomes independent) Manchukuo, taking precedent over the fascist system and consisting of Imperial Protectorate -> Imperial Associate -> Independent, with a special Imperial Subject tier in-between Associate and Independent that Manchukuo can become through a focus.
• The Purge:
  • The Great Purge can be conducted by the Soviets. There's good reasons to do it, though if playing a long game, many Soviet players will avoid it and gain control through less brutal means. In IV, it's possible to have Trotsky taking the power in Soviet Union, which results in another purge. The reworked Soviet focus tree has a much more complex series of purges akin to the real life ones, and also has random events that can purge advisors, generals, or grant other debuffs.
  • Darkest Hour for HoI2 has a generic Purge-like decision. Using it gets rid of "disloyal" generals.
• Railroading: In the third installment, the British will always declare war on Germany by 1941, even if they're allied with Poland, have the United States in their sphere, or didn't even annex Austria. If you make use of the "noneutrality" cheat, your threat will shoot through the roof very quickly, so Britain may actually declare war on you specifically for annexing Austria, the Sudetenland, or Czechoslovakia.
• Red Baron: Ace Pilots always come with nicknames. If they are a historical figures, it's their real call sign.
• La Résistance:
  • It's possible for partisan groups to form if unrest is high enough, with this generally being significantly more likely in occupied or colonized territory than in your home nation. High partisan activity can positively cripple a country's infrastructure, and eventually may lead to open revolts in which the partisans organize and outright seize territories from their host nation. The Mass Assault land doctrine in the fourth game has the final skill in the Mass Mobilization tree give a huge +20% bonus to partisans, which often results in lots of factories being sabotaged.
  • The For The Motherland expansion will allow players to build "Underground" commando units to arm and mobilize resistance units in enemy-occupied territory, allowing for anything from subtle partisan resistance to sudden revolts and large-scale assaults by well-equipped rebel formations. This can be used to play merry hell with an enemy's supply infrastructure. In fact, this is one of best weapons a government-in-exile has available to it.
  • High revolt risk disrupts supply, which can seriously downgrade an army's fighting capability, even when there are no active rebels. This represents sabotage and various other acts of passive resistance.
  • In IV, prior to the La Résistance DLC, resistance consists in random acts of sabotage in an occupied territory (which translates in-game to factories being temporarily crippled) for as long as the current war lasts, then they completely stop when the war is finished (even in territories which are forcibly puppeted or annexed by the victor). La Résistance adds a complex overhaul of the system, notably making resistants still active in annexed areas after a conflict's official end.
• Rightful King Returns: Many states have options to restore monarchy by selecting the relevant national focuses, including Nazi Germany.
• "Risk"-Style Map: Hundreds of provinces. The third installment has somewhere in the region of ten thousand regions, achieved by subdividing territories and provinces into smaller areas that must be fought over individually. The fourth installment has even more, but makes the bloat less notable by making provinces nameless and relevant purely for unit movement; they're essentially somewhat irregularly shaped hexes. Everything except unit movement - production, resources, infrastructure and supply - is handled at the level of 'states', of which there are a mere few hundred.
• RPG Elements:
  • Cabinet ministers and military leaders have different traits which have varying effects on the nation, diplomacy, the military and the troops under their command.
  • Then there is the experience meter for units and leaders. Experience of units is transmitted directly into their combat effectiveness, while leaders can gain new traits (HoI2) or grant bigger combat bonuses (HoI3)
  • The third installment introduces "strategic effects", which you can gain or loose depending on certain conditions, such as joining a faction, fighting enough battles, controlling a strait or canal, or holding enough provinces to dominate a body of water like the Baltic or the North Sea.
  • Their Finest Hour now allows generals to develop combat traits in addition to the ones they already possess, including new terrain traits like "Jungle Rat" or "Hill Fighter".
• Running Gag: Each DLC from Waking the Tiger to No Step Back for IV adds a new secret identity for Hitler, usually as a leader for another country if he's deposed in the German Civil War.
  • Waking the Tiger makes it possible for him to shave his mustache, flee to Argentina, adopt the pseudonym Señor Hilter, and become the leader of Argentina's fascist party.
  • Man the Guns introduced a second fake identity as the enigmatic American architect Adam Hilt and allows him to take power as an alternative to William Dudley Pelley and Douglas MacArthur if the fascists win the Second American Civil War.
  • La Resistance introduces two alternate personas for Hitler as spies, one of which has him Disguised in Drag.
  • Battle for the Bosphorus adds the possibility for him to shave his head, put on a fake beard, fake noble lineage, and claim the throne of a restored Byzantine Empire as Emperor Adolfos I.
  • No Step Back broke the trend, but made a joking reference to the Intended Audience Reaction of Stalin fleeing to South America and putting on a Paper-Thin Disguise in the news event for the Soviet Union being defeated in a civil war^note said DLC revamped the focus tree for the Soviet Union, and added three possible civil wars that can see Stalin overthrown.
• Schizo Tech: Bike battalions are present in IV for Japan, the only country that used such infantry in any meaningful quantity or success. They have virtually the same stats as regular infantry, but move much faster. They also make a great tandem with heavy tanks out of all things, since they both have similar speed and are faster than foot infantry.
• Second American Civil War: One of the main selling points of the Man the Guns DLC for IV is a pair of radical alternate history routes for the USA enabling the country to become fully fascist or communist, with a Second American Civil War being necessary to each route implementing their radical ideology change.
  • In one, FDR goes much further in his New Deal policies and allies with an emboldened Communist Party of the United States of America to expand his support base, resulting in conservative elements launching a civil war to try to stop the country's march towards communism. If they are defeated, much like the Confederacy before them, their civil war brings up the very thing they sought to prevent as they have essentially removed themselves from American politics and the CPUSA actually does take power.
  • In the other, FDR is defeated in the 1936 elections and his opponents ally with the Silver Legion to try solidify their power via voter intimidation and other shady practices. Seeing this as a sort of "soft coup", FDR and the progressive wings of the Democratic and Republican parties, calling themselves the Constitutionalists, start a civil war, while Douglas MacArthur assumes command of the Loyalist forces. If the Loyalists are victorious, MacArthur can retain power or the Loyalists can establish a new Confederacy under the rule of William Dudley Pelley, Charles Lindbergh, or if the Kaiser has been restored in Germany, an architect named Adam Hilt, who is very definitely not an exiled Adolf Hitler in disguise. After which, the new far-right regime can attempt to leverage the vast American economy and population into world conquest.
• Selective Historical Armoury: Some of the equipment and vehicles used in IV are a bit... odd.
  • Canada uses the American M50 Reising SMG^note They only received limited numbers, and only gave them to units stationed in Canada to guard POW camps. Even in US service, it wasn't widely used, and was withdrawn from frontline service due to reliability issues instead of the Sten^note which they not only used in far greater numbers, and used on the frontlines, but a fair number were actually produced in Canada or the Thompson ^note  Which was the standard-issue SMG before the Sten, and remained in widespread use in the Mediterranean theater , and the M1944 Johnson LMG^note Even rarer in US service, with only 9500 being produced, and the only Canadians to use it were members of the joint US-Canadian First Special Service Force. Also redundant, since the Canadians already get the Bren LMG, instead of the Sterling SMG^note Like the Sten, it saw wider use, and not only was it produced in Canada, but they produced a specific variant for themselves, the C1, which had a removable trigger guard to make it easier to use in the Arctic. Though it wasn't adopted until 1958, when it replaced the Sten. They also use the Austin K5 truck^note Made in Britain starting in 1941, only 12,280 produced, mainly used by the British instead of the Canadian Military Pattern (CMP) truck^note Made in Canada starting in 1940, over 500,000 produced, used by almost every nation of the Commonwealth, as well as the USSR and several smaller Allied nations, especially egregious since the production of the CMP and several other trucks was one of Canada's largest contributions to the war effort^note To the point that the British Government's official History of the Second World War views it as being Canada's greatest contribution, which is saying something when you take into account Juno Beach and their other contributions in France, the Netherlands, and Italy.
    • In a reversal of the trend, they have the Ram and Grizzly tanks instead of the Sherman, despite the fact that neither ever saw combat service as a gun tank (the Ram was mainly used for training, or converted into various other vehicles, primarily the Ram Kangaroo APC. The Grizzly was just a Canadian built M4A1 Sherman, and most were turned into Sexton Self-Propelled Guns. Only 180 of them were made, and they saw only two years of service in the Canadian army^note Though they saw about three decades of service in the Portuguese Army)
  • The Soviet Union's infantry sprites are all shown using the Tokarev SVT-38/40 as their main service rifle, instead of the far more famous and common Mosin-Nagant 91/30. The SVT-38/40 was considered too complicated for normal infantry use, and was given to snipers and elite troops instead.
  • The Czech infantry sprites use the rare ZH-29 semiautomatic rifle instead of the famous vz.24, considered one of the best Mauser-pattern rifles ever made, and built in the millions.
  • While their sprites are shown using bolt-actions, the Polish forces are issued the Kbsp wz.1938M semiautomatic rifle. This is particularly egregious as only 150 were built and they were at the prototype stage when the war started, while practically all Polish soldiers used the bolt-action Kbk wz.29 instead.
  • Australia starts off with the Lee-Enfield No. 4 Mk I...which they didn't even produce in real life, sticking with the SMLE No. 1 Mk III* model for the whole of the war. India also uses it when they used the No. 1 Mk III* in real life. New Zealand has the No. 4 Mk I unlocked for their 1936 service rifle, yet historically they only replaced the No. 1 Mk III* in 1945. Especially odd is that their infantry sprites are correctly modeled to use the No. 1 Mk III*.
  • New Zealand also can utilise the Bob Semple 'tank', which was never seriously considered for deployment and widely ridiculed within New Zealand even in its own time.
• Shout-Out: Plenty, especially in the achievements and ahistorical focuses in IV.
  • "Poland Can Into Space" which is gained from reaching all Rocket Technologies as Poland is yet another entry in Paradox's Running Gag references to Polandball.
  • For commanders with the trait "Logistics Wizard" the description is as follows: Supplies are never late, nor ever early, they arrive precisely when I mean them to.
  • "Med plutonium..." which is gained from nuking Denmark while playing as Sweden, is a reference to Riget, wherein the Swedish Dr. Helmer goes on angry rant about Denmark, which includes the line "Med plutonium tvingar vi dansken på knä!" ("With plutonium we bring the Danes to their knees!")
  • "Our Words Are Backed By Nuclear Weapons", which is gained by developing a nuclear arsenal as India, is a reference to Civilization (where the Indians under Gandhi really liking to nuke everyone became a Running Gag).
  • "Duce Nuked'em" is pretty obvious.
  • There is a focus in the secret Papal tree from By Blood Alone called "Il Vento Aureo". The Flavor Text includes the phrase "This will be our greatest Requiem!"
  • "District 9" is gained by building 9 factories in the Transvaal.
  • New Zealand can go fascist by choosing the national focuses "In the Darkness" and "Rule Them All".
  • "Nobody expects..." is gained by conquering France as Spain.
    • "Our Chief Weapon Is Surprise" - requires staging 5 coups against other nations as Spain.
    • From a different sketch, the "Mr. Hilter" sketch: "Not Much Fun In Stalingrad" - as Germany, capitulate the USSR without taking Stalingrad.
  • "The Bell Tolls for Us" requires winning the Spanish Civil War as the Republicans.
  • The flavor text for the UK's "British Stoicism" national spirit is from Kipling's poem "If—".
  • "Miklos Horthy and the Habsburg Prince" (received if the player restores the Austro-Hungarian Empire as Hungary) should be obvious.
  • The achievement "The Empire Strikes Back", for declaring war on a former Commonwealth state as the UK.
  • The achievement "The Good, the Bad, the Weird", for developing a strong oil industry as Manchukuo.
  • The "Romance of the Three Kingdoms" achievement, for puppeting and annexing Guangxi and Yunnan as China.
  • The "Make a Man Out Of You" achievement, for having a million manpower for deployment as a Chinese warlord.
  • The "Assuming Direct Control" achievement, for starting out as a minor state and becoming the leader of the Allies, Axis, or Comintern. To complete the reference, the icon is Stalin with the characteristic glowing yellow Mind-Control Eyes.
  • "Go Ahead, Macau My Day" requires a Portuguese puppet state conquering all of China.
  • "Bad Romeance" requires forming Byzantium as Greece and puppeting Italy, Russia and Romania.
  • "Georgia On My Mind" - as the United States control Georgia (the state), Georgia (the country) and (South) Georgia (the island).
  • "Finnish Him!" - as Finland, defeat the Soviet Union without joining a faction.
  • "We Will Rock You" - as Spain, conquer Gibraltar.
  • "Pride and Extreme Prejudice" - sink the UK's flagship.
  • "My Ships Don't Lie" - form Gran Colombia and have 10 battleships and carriers.
  • "House of Kurds" - form and unite Kurdistan.
  • "Tojo Shot First" - as Japan, nuke the US before they have developed nukes.
  • "Team America" - as the United States, nuke Paris.
  • "Istanbul is Constantinople. Again." - as Greece, conquer Istanbul.
  • The American alt-history path has an option where you can demand Canada give some of its land to you. If they refuse, declining the war goal you'll receive is labeled with the message "What do we want with a bunch of rocks and trees?"
  • "Not much fun in Stalingrad" - as Germany, capitulate the Soviet Union without conquering Stalingrad.
  • Having the same spy captured twice gives the achievement "Man of a Thousand Faces, Every One the Same", picturing "Monsieur Leclerc" in his characteristic pose.
  • There are also several Shout Outs to Paradox's other grand strategy games:
    • The event "Komet Sighted" is a reference to an infamous Europa Universalis event that destabilizes the country.
    • The achievements "Crusader Kings" and "Crusader Kings 2" require, respectively, a fascist South Africa under Edward VIII conquering Jerusalem, and a communist black nationalist South Africa leading an anti-colonial crusade. "Crusader Kings 3" breaks the trend somewhat, as instead of requiring a non-aligned South Africa for an achievement^note outside of being puppeted by a non-aligned nation or using console commands, South Africa can't adopt said ideology, it requires Poland to go monarchist and capture Jerusalum. "Crusader Kings IV" followed in the footsteps of "III" by having Ethiopia require to control Jerusalem and make it your capital.
    • The "Sunset Invasion" achievement, requiring you to invade Europe as Mexico, is a reference to Crusader Kings 2's DLC of the same name that featured an Aztec invasion of the continent. There's also "Sunrise Invasion" for invading Europe via Mexico as Japan.
  • When recruiting randomly-generated generals as United Kingdom (or another of the nations sharing the British culture), one of the portrait is Sean Connery dressed in the same uniform he wears in A Bridge Too Far.
  • Similar to the above, when recruiting spies in the La Resistance expansion of IV, on top of both randomly generated and historical agents, players may be able to recruit the likes of James Bond, Henry Jones, and Hans Landa. Additionally, among the recruitable historical agents are the likes of Ian Fleming^note who served in British Naval Intelligence and Christopher Lee.^note who was in RAF Intelligence and later served with the Special Operations Executive and with various Special Forces units.
  • The "Play It, Sam" achievement for having a spy network of 50% or more in Casablanca.
  • Fulfilling the Megali Idea in Battle for Bosporus earns "This Is Madness" achievement with Leonidas' face on the icon.
  • "Pizza Time!" is gained by conquering New York, Chicago and Hawaii as Italy.
  • "Snakes on a Plane" can be gained by playing as Brazil and taking over Rome via paratroopers.
  • The achievement for Ethiopia controlling Kenya and Tanzania is The Lion King, complete with the icon being the lion in the flag of Ethiopia on Pride Rock.
  • The event for the Blaco party winning the 1938 elections in Uruguay is acknowledged with "A surprise to be sure, but a welcome one."
• Space-Filling Empire:
  • Regardless of game, after pushing back Germany (and potentially Japan), Soviet Union facas a choice: either creating a whole lot of puppet states in "liberated" areas, or annex them directly. This can potentially mean Soviet Union including even France and Italy, while simultaneously taking over Manchuria and Korea, along with Japanese Home Islands.
  • Similarly, once Soviets are beaten, Germany stretches from France to Urals at the very least and can go further, taking over all of the USSR. If this happens, Allied attempt to take take back Europe is doomed to fail.
  • AI is capable 9 out of 10 times to conquer as Japan all of China, South-East Asia and Indonesia. Under human control, it's relatively easy to add all of India into the mix and going crazy with Australia and New Zealand, which stand no chance whatsoever when facing direct invasion. All of which can be achieved by about '41 mark with relative ease. By then, just attack Soviet Far East, as the Red Army will be too busy fighting against Germans to have there any troops beyond token garrisons to even think about stopping you.
  • Italy, under player control, is probably the most prominent example of an "empire" that ends up taking a lot of ground that's utterly worthless: namely, Sahara desert and Sahel region. AI will never manage to pull that, but under human control, Italy is still locked in fighting over utterly worthless territories, short from controlling Suez Canal and maybe taking over Iraqi oil fields. If you really stretch it, Italy can take over most of Africa and it will have close to zero value in terms of HoI mechanics, but outstretch Italian logistics to a breaking point half-way through.
  • In IV (with Man the Guns), playing as United Kingdom allows to make a series of decisions which would eventually result in the creation of the Commonwealth of Nations/Commonwealth of People/Empire/Imperial Federation (respectively the new country's name if democratic, communist, fascist, or non-aligned), a single country occupying the former territories of United Kingdom, United States, Canada, India, South Africa, Australia, and New Zealand. Unlike other examples, this can be achieved by not firing a single shot.
• The Starscream: In Republican Spain, the Stalinists are loyal members of the Popular Front government, and will be happy to help defend the country against the Fascist threat and those anarchists who threaten the unity of the Front. They just want some positions in the government...and if they get them, they'll take control and abolish democracy.
• Suicide Attack: Several countries, including Japan, the Soviet Union, and various fascist or communist minors can unlock the Kamikaze mission, which causes the plane to do several times its normal naval attack at the cost of both plane and pilot. Japan can take this up to eleven with a focus that unlocks the Yokosuka MXY-7 Ohka rocket-powered manned bomb, which is a purpose-built plane that is only capable of Kamikaze attacks and is absolutely devastating at them.
• Tactical Withdrawal: Both on the strategic and tactical levels. Players may well choose to pull back from a section of their line in order to withdraw from an obviously lost fight towards better terrain/reinforcements or they may be pulling the attacker into an encirclement trap assisted by the rest of the front line and reserves. Defending generals with the right doctrine or who are just lucky can also get it; it shortens the front, leaving attacking and defending units who take up more room than the front allows Locked Out of the Fight, and gives the defender a net advantage (both sides are penalized in their attack chances.)
• Take Over the World: It is indeed possible (but difficult) to do this. Even as Luxembourg, as demonstrated here. Percentage of world conquered is one of the statistics measured by the end screen, and you even get a specific achievement ('One Empire') for taking over the entire world as the United Kingdom.
• Take That!: Originally, the cheat code that makes AI agree on any diplomatic proposal in II was "neville". It was later replaced with "yesman''.
• Taught by Experience:
  • Units start on specific level of training, ranging from barely organised conscripts with few days of training to well-drilled, but never tested in combat troops. At least in IV divisions can be ordered to perform exercises, increasing their competence outside of combat to a certain level. However, the main source of experience for troops beyond training comes from fighting. Depending on game, this can go as far as provide whooping 75% bonus for hardened veterans, but it takes months or even years of very intense combat to reach that level and each replacement in the division decreases that value.
  • Officers in charge of troops start with scripted level and traits. From then on, only by leading troops in battle (or commanding other officers in a larger front/theatre) they can increase their skills, both in form of general commanding competence and specific traits, like bonus for specific type of troops or terrain. Excluding IV, there is also a scripted Cap on how high the skill of each commander can go, which means some of them will never be good, while other will run out of wars to fight before hitting their limit.
• The Strategist: Any commander with Brilliant Strategist and Organizer traits becomes one, having a considerable advantage in forming battle plans
• Title Drop: Not for base game, but for add-ons. Arsenal of Democracy is the USA. Darkest Hour has one in 1914 scenario, though player doesn't usually sees it, as he either wins, or quits game before he sees it: Any major nation defeated in World War One has final surrender event, which results in most its remaining army disbanded, disputed territory ceded to enemy, and being forced to pay high reparations, all of that without option to fight on despite the odds, or trying to negotiate with winner imposing his conditions. The only option in those events is, appropriately: "Germany Lives its Darkest Hour", "France Lives its Darkest Hour", "Russia Lives its Darkest Hour", etc.
• United Europe:
  • The European Union can be formed by any of the founding nations of the real life European Coal and Steel Community^note Belgium, France, Italy, Luxembourg, The Netherlands, or Germany by controlling the core territory of those six states.
  • Other ways of uniting Europe include the Greater German Reich (as a fascist Germany, include Paris, Leningrad and Stalingrad within your territory), the Nordic League (Denmark, Finland, Iceland, Norway, and Sweden) and the Roman Empire (as fascist Italy, control the territory of the Roman Empire at its greatest extent).
• Urban Warfare: Urban terrain types cause your units to suffer penalties in combat, with armor and artillery suffering the worst and infantry suffering the least, especially with engineers attached^note Their Finest Hour gave Germany motorized Waffen-SS special units that have bonuses for fighting in urban areas and repressing locals. Since urban provinces are also almost always victory point provinces or capitals, this also means plenty of hard-fought battles to take these cities.
• Villains Act, Heroes React: The democratic powers have far larger economies and populations than the Axis powers at the start of the game, but can't do anything about fascist aggression until 'belligerence' (in II and its derivatives), 'threat' (in III), or 'world tension' (in IV) reaches certain levels. Democracies are also limited in their ability to conscript soldiers and channel their industries into military production before the war starts.
• Violation of Common Sense:
  • In III, for vast majority of nations, the "Consumer Products Orientation" is the superior choice for industrial policy during peace time, doing military build-up and expanding the infrastructure, despite providing -10% penalty to your IC. Yes, "Mixed Industry" might provide you with flat increase to your IC and production efficiency, but it also sharply increases consumer goods demand to the point where it will outweigh all the bonuses. On top of that, a in-game pointer will constantly remind players to impose the "superior" policy of Mixed Industry.
  • In IV, at least with Man the Guns DLC, the best way of killing heavily armed and well-armoured capital ships is to completely ignore heavy gun batteries and your own armour and instead go for the cheapest ship class, destroyers. Just arm them through the nose with equally cheap torpedo launchers. A sufficiently large DD flotilla will obliterate everything on its path and even if suffering loses, you can just build more of them in few weeks, while even repairing a damaged capital ship knocks it out of service for months, while building new one is a matter of years.
    • Similarly, in IV, if you're at war with a country and need to annex another to gain cores on them, one completely viable option is forming a faction with the latter country. Doing so will let you call them into the war, and if you wait long enough, you can then kick them, which will not only prevent them from joining another faction, but will also result in them getting annexed, meaning that when you do capitulate the country you were originally at war with, you'll be able to annex 2 or more countries for the price of one.
• War Is Hell:
  • Much of the game has a bleak, depressing atmosphere. While many strategy games represent huge armies as single units with nondescript "hit points", Hearts of Iron represents units as divisions of thousands of troops, who tend to die in large numbers when armies clash. Fighting a war and receiving reports of tens of thousands of soldiers losing their lives in a single battle can be very sobering.
  • A lot of the historical quotes seen in the loading screens of Darkest Hour exemplifies this.
  • Even the map is darker and more subdued than other Paradox titles. This, combined with a very utilitarian interface, this makes for a very different game experience than, say Europa Universalis or Victoria.
  • If you've activated popups that report the effectiveness of bombing missions, it can get even more sobering, especially once you start teching up your tactical bombers. Seeing regular reports of a wing of bombers killing three hundred enemy soldiers in every strike, with six or so airstrikes a day, for weeks on end, can really put a perspective on things.
  • Made even worse with Hearts of Iron 4, where as you fight a war you get a constantly updating casualty list that can go into the millions or tens of millions, depending on how long the war lasts and the size of both countries.
• We ARE Struggling Together: IV put a far more focus on the internal situation of various countries than previous entries in the series:
  • How the Spanish Civil War plays out with the La Resistance pack installed. If playing with historical focuses turned on, the anarchists in Catalonia will turn against the republican government, and both will fall to Franco's unified nationalist forces. (Truth in Television, as this badly crippled the Spanish republicans in real life.) If historical focuses are turned off, it can go both ways, with the nationalists splitting between the Falangists and the Carlists while the Republicans and Anarchists go at it, producing a four-way civil war.
  • The initial situation in China isn't much better. The central government controls less than half of the country, each warlord, regardless of political path taken, will try to usurp it one way or another and the communists are busy infiltrating surrounding provinces and indoctrinating farmers to stage country-wide revolt. If steps aren't taken from the start to put things under control, Chinese government can easily find itself in a three-way war in the middle of a Japanese invasion, while the warlords will be busy fighting each other and the IJA.
  • After No Step Back DLC changed Polish focus tree, it how has to carefully balance its dictatorship, and placating one side instantly angers the other. It is entirely possible for Poland to be so preoccupied on managing its internal politics, it will be caught even more unprepared for war than it did in real life thanks to the exact same political issues.
  • Central and Southern Europe in general is easy picking for Germany and Soviets without firing a single shot, precisely due to every single country being scripted to handle things on their own, rather than go for local alliances. Czechoslovakia and Poland can easily oppose German invasion when allied, but will not pursuit such path, being busy with internal politics. Baltic countries will rather build fortifications between each other than on Soviet border. In the south, Yugoslavia is barely an unified country, with each part of it trying to break out for independence, and will get rolled over by Italy even without German assistance, being too busy with politics to defend itself.
• We Have Reserves: If your manpower laws and focuses give you a good enough manpower pool you can start to have this attitude, though at the same time it's actually played with; having too many troops in a certain area can stretch your supply situation to the point where your units suffer attrition.
  • A truly egregious case happens in IV with Nationalist China. Even at lowest possible conscription level, you are going to have millions of reservist, as the game is incapable of representing KMT's problems with getting conscripts and instead just draws a percentage from Chinese population. AI doesn't understand that, so it pushes for extreme recruitment policies, ending up with more than 50 millions of potential manpower and constantly building new units, as the AI scripts consider that to be a massive overflow that should be quickly turned into more divisions.
• World War III: Happens 8 times out of 10, given the fact that the victors (for instance, the Allies and the Comintern) tend to fall out over the spoils in a pretty dramatic fashion. Though the AI isn't particularly great at naval invasions.
• Video Game Caring Potential: One update to IV gave the player the ability to construct certain buildings^note Infrastructure, Railroads, Air Bases, Supply Hubs, and Ports in the territory of an allied country^note the player could construct buildings in puppets at certain levels, but this update allowed for them to construct in independent countries. While railroads benefit the player's troops as well, infrastructure will boost the speed of all buildings constructed, meaning that doing so can allow for them to get factories out faster, thus meaning they have more equipment available for when they are attacked.
• Video Game Cruelty Potential: Once you have built nuclear weapons, you could declare war on a defenseless country like Haiti and nuke it, over and over again. Even using a cheat to give yourself nukes just so you can nuke Haiti or other defenseless countries, several hundred times.
• You Have Researched Breathing: Zig Zagged, depending on the technology. Some technologies, like airplanes or warships, might make sense for some countries to not have models for even the most basic of equipment. For others, like artillery (a type of weapon that has been around for centuries, with rifled cannons being around since the 1840s and "modern" cannons with hydraulic recoil control being invented in 1897) or civilian trains (as of the No Step Back DLC), it makes much less sense. Countries like Mexico can bafflingly have rail systems set-up by default, but still haven't researched the basic civilian train.

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