History YMMV / HeartsOfIron

** In ''IV'', after Turkey got a unique focus tree in ''Battle for the Bosporus'' it quickly became one of the most despised countries to play. Its focus tree is considered overly large and time consuming, with many, many 70 days focuses that must be completed just to fix the country's political problems. By the time you do and are ready to start expanding (assuming you did one of the alternate history options, which, to be fair, aren't half bad), the whole world will be on fire and you must now fight entire factions by yourself. And if you did the historical path? Then it's the same problem as historical USA, on steroids: you don't do anything usually until 1943 or 44. As such, Turkey is largely held up by the fanbase as an example to Paradox of what ''not'' to do when making unique focus trees.

** In ''IV'', Central and South American nations are generally mocked by the player base. They typically have very little impact on gameplay but have a major impact on game performance, as the AI will favour doing nothing but spamming units the entire time but never declaring war[[note]]El Salvador is a meme in the community for sitting on its two tiny provinces and doing nothing but creating dozens of units[[/note]]. The terrain in the regions is primarily jungles, swamps and mountains as well as impassable regions making logistics nigh-impossible, made even worse by the new logistic systems added in ''No Step Back'' and the penalties regarding mountain regions added in ''Arms Against Tyranny''. Finally, due to the Monroe Doctrine by the US, if any non American nation decides to invade the hemisphere America will instantly intervene. Even with the [[AuthorsSavingThrow serious adjustments and improvements added to the entire region]] in ''Trial of Allegiance'' to make the experience more bearable, the terrain and logistics of the region still remain a persistent issue.

** In ''IV'', Central and South American nations are generally mocked by the player base. No nation south of Mexico has a unique focus tree, leading to very little action in the entire region. They typically have very little impact on gameplay but have a major impact on game performance as the AI will favour doing nothing but spamming units the entire time but never declaring war[[note]]El Salvador is a meme in the community for sitting on its two tiny provinces and doing nothing but creating dozens of units[[/note]]. The terrain in the regions is primarily jungles, swamps and mountains as well as impassable regions making logistics nigh-impossible, made even worse by the new logistic systems added in ''No Step Back'' and the penalties regarding mountain regions added in ''Arms Against Tyranny''. Finally, due to the Monroe Doctrine by the US, if any non American nation decides to invade the hemisphere America will instantly intervene. Even with the [[AuthorsSavingThrow serious adjustments and improvements added to the entire region]] in ''Trial of Allegiance'' to make the experience more bearable, the terrain and logistics of the region still remain a persistent issue.

** In ''IV'', Central and South American nations are generally mocked by the player base. No nation south of Mexico has a unique focus tree, leading to very little action in the entire region. They typically have very little impact on gameplay but have a major impact on game performance as the AI will favour doing nothing but spamming units the entire time but never declaring war[[note]]El Salvador is a meme in the community for sitting on its two tiny provinces and doing nothing but creating dozens of units[[/note]]. The terrain in the regions is primarily jungles, swamps and mountains as well as impassable regions making logistics nigh-impossible, made even worse by the new logistic systems added in ''No Step Back'' and the penalties regarding mountain regions added in ''Arms Against Tyranny''. Finally, due to the Monroe Doctrine by the US, if any non American nation decides to invade the hemisphere America will instantly intervene.

** ''Hearts of Iron'' player touches Brest[[labelnote:Explanation]]A joke concerning the stereotype that all ''[=HoI=]'' players are basement-dwelling history nerds, and the only "breast" they'll ever "touch" is landing a naval invasion at the [[HehHehYouSaidX city of Brest]] in western France.[[/labelnote]]

** The French enclave on the Southern Chinese coast is historically accurate. It's the [[https://en.wikipedia.org/wiki/Leased_Territory_of_Guangzhouwan Leased Territory of Guangzhouwan]], which was ruled by France between 1898 and 1945, administrated as part of French Indochina from 1900 to it return to China.

** The United Kingdom wields its navy as an impenetrable shield around Great Britain, meaning the only way you can pull off a naval invasion is by investing heavily in a navy (which is not at all practical for some countries) or building legions of naval bombers, which will need air escortion to prevent Britain from shooting them all out of the sky. alternatively, you could try and go for total air superiority and invade with paratroopers, but this is risky and heavily dependent on your troops being able to reinforce them in time.
** The United States is annoying as hell for basically being the only country with a ''hemisphere'' all to itself, making it very difficult to invade whatsoever if you're not playing as the UK. Not to mention you're basically on a super strict time limit to defeat them before their industry kicks into high gear, as virtually no Major Power by itself can compete with America's mobilized industry and it will make capitulating them that much harder.

* SequelDisplacement: It's easy to tell by player counts that the majority of ''Hearts of Iron'''s playerbase began playing starting with ''IV'' except for a much smaller old guard contingent of players who have been playing since ''II'' (and even smaller group sticking since the original game), due to ''IV''[='=]s paring down of the more confusing gameplay elements and adopting a more striking, less "spreadsheety" visual style causing a large NewbieBoom for the series. It also helps that ''IV'' is the easiest one in the series by far, both to play and to mod, allowing players to readily get into the game right off the bat, rather than spending hours reading in-depth guides and wikias to even try playing - even if it also causes a lot of disdain from the old guard for making "[[PretenderDiss kid-friendly HoI]]", it undeniably had an explosive effect on the size of the playerbase.

* SequelDisplacement: It's easy to tell by player counts that the majority of ''Hearts of Iron'''s playerbase began playing starting with ''IV'' except for a much smaller old guard contingent of players who have been playing since ''II'', due to ''IV''[='=]s paring down of the more confusing gameplay elements and adopting a more striking, less "spreadsheety" visual style causing a large NewbieBoom for the series.

** In ''IV'', if you want to release a nation or form a Collaboration Government, you have to release all states they own...even if one of the states they own is a core of yours. Wanna release France as a puppet after forming the Holy Roman Empire so you can steal their manpower? Say goodbye to Savoy and Alsace-Lorraine. An especially annoying version of this is if the country you're trying to release ''gains'' a core on a state - if Poland annexes Germany and then gets enough compliance to form a collaboration government, if Germany did Danzig or War, Poland will lose Danzig in the process.

* UnderusedGameMechanic: At a certain point in ''IV''s development, each new DLC started to introduce new sets of modifiers and eventually fully-fleshed mechanics that are specific to a ''single'' country - or even just a single country ''tag''. Examples include, but aren't limited to stuff like the US Congress' support, Nationalist China's (and ''only'' that specific Chinese nation) inflation, Turkish republicanism, Stalin's paranoia or Polish and Italian factionalism (both handled as their own separate mechanics, working differently). Those gameplay elements are '''never''' used in a broader context or as actual mechanics affecting every nation, nor are they introduced retroactively to nations that could benefit from them, instead becoming nearly esoteric mini-games that players have to deal with whenever playing as an affected country. And that without mentioning the status of the majority of those as ScrappyMechanic.

* SugarWiki/AwesomeArt: The [[https://www.youtube.com/watch?v=WEN5SEb5ASA pre-order trailer]]. Unlike other trailers which use stock images and footage, this one has awesome Soviet propaganda-styled artwork.

** The French enclave on the Southern Chinese coast is historically accurate. It's the Leased Territory of Guangzhouwan, which was ruled by France between 1898 and 1945, administrated as part of French Indochina from 1900 to it return to China.

* JustHereForGodzilla: [=HOI4=]'s extremely active and highly popular modding community has resulted in many players getting [=HOI4=] just for the mods, often completely ignoring the base game.

* AluminumChristmasTrees: Upon release of the related DLC, the concept of a focus tree giving Estonia oil as a resource was scoffed off as absurd and gamey. In real life, Estonia has huge deposits of oil shale, which it started to use industrially [[https://en.wikipedia.org/wiki/Oil_shale_in_Estonia#Developments_in_interwar_Estonia during the interwar period]] - just not for fuel production.

** If you deleted all but one division, exercising it would give you tons of army XP. This was unsurprisingly patched.

** ''IV'''s focus trees continuing to give countries unique mechanics that usually influence the focuses you can take (unofficially called "{{Minigame}}s" by the fanbase) has split the community four ways. The first camp says that they're universally annoying distractions that are banal to keep track of on top of everything else in a massive grand strategy game. The second camp points out that the alternative is focus trees like Yugoslavia and France, which require the player to sit around until 1939 waiting for focuses to complete before being able to actually do anything interesting, which is boring and time-consuming in and of itself. Finally, a third group enjoys specific "Minigames" like Bulgaria's which provide something engaging to do while progressing the tree, but acknowledges that certain ones like Switzerland's are both confusing and obnoxious to the average player. And finally, there are people who don't mind the minigames themselves... if they were universal game mechanics, rather than country-specific stuff, especially when there can be two or even three different minigames to ultimately tackle the exact same thing.

** ''IV'''s focus trees continuing to give countries unique mechanics that usually influence the focuses you can take (unofficially called "{{Minigame}}s" by the fanbase) has split the community three ways. The first camp says that they're universally annoying distractions that are banal to keep track of on top of everything else in a massive grand strategy game. The second camp points out that the alternative is focus trees like Yugoslavia and France, which require the player to sit around until 1939 waiting for focuses to complete before being able to actually do anything interesting, which is boring and time-consuming in and of itself. Finally, a third group enjoys specific "Minigames" like Bulgaria's which provide something engaging to do while progressing the tree, but acknowledges that certain ones like Switzerland's are both confusing and obnoxious to the average player.

** The Stalin Paranoia mechanic being introduced really bought to a head complaints & arguments in the fanbase about Paradox stuffing the game full of what the community call "mini-games" where you have to manage esoteric country specific mechanics that do away with the regular way of managing your country. These include certain civil wars having you build support per province, border conflicts, the US congressional politics mechanic that no-one else in the game uses, Turkish, Dutch & Greek investment decisions, the Chinese warlords and the Bulgaria focus tree, or the Italian, Ethiopian and ''Swiss'' balance of power mechanics.
** Any country that has a focus tree without a ''single'' 35-day focus, because it's such a chore to work your way through it, especially if you're basically on a time limit and another country will usually declare war on you by 1938. The worst offenders of this are probably Yugoslavia, whose focus tree is confusing on top of all this, and ''France'', of all countries, because its' focus tree has so many individual paths to go down

* UnderusedGameMechanic: At a certain point in ''IV''s development, each new DLC started to introduce new sets of modifiers and eventually fully-fleshed mechanics that are specific to a ''single'' country - or even just a single country ''tag''. Examples include, but aren't limited to stuff like the US Senate's support, Nationalist China's (and ''only'' that specific Chinese nation) inflation, Turkish republicanism, Stalin's paranoia or Polish and Italian factionalism (both handled as their own separate mechanics, working differently). Those gameplay elements are '''never''' used in a broader context or as actual mechanics affecting every nation, nor are they introduced retroactively to nations that could benefit from them, instead becoming nearly esoteric mini-games that players have to deal with whenever playing as an affected country. And that without mentioning the status of the majority of those as ScrappyMechanic.

* LowTierLetdown: Ever since army doctrines were introduced in ''II'', Grand Battle Plan is consistently overshadowed by better picks, is clearly weaker than alternatives, requires some specific gimmick to shine or any combination of the three. In ''II'' and ''Darkest Hour'' it is particularly awful due to the way how research works in those. Since research is done by tech teams and they come with pre-definied specialisations, chances are if your country has a team geared for researching Grand Battle Plan doctrine, it won't have alternative doctrinal team. And researching lackluster doctrine is still better than trying to catch-up in different field without a specialist.

** In ''IV'', Central and South American nations are generally mocked by the player base for a multitude of reasons:
*** No nation south of Mexico has a unique focus tree leading to very little action in the entire region.
*** They typically have very little impact on gameplay but major impact on performance as the AI will favour doing nothing but spamming units the entire time but never declaring war. El Salvador is a meme in the community for sitting on its two tiny provinces and doing nothing but creating dozens of units.
*** The terrain in the regions is primarily jungles, swamps and mountains as well as impassable regions making logistics nigh impossible, made even worse by the new logistic systems added into the game.
*** Due to the Monroe doctrine by the US if any non American nation decides to invade the hemisphere America will instantly intervene.

** In ''IV'', the Commonwealth countries are generally considered lackluster to due to their focus trees (which were the first DLC ones released with ''Together For Victory'') having aged very poorly in terms of rewards and alternate history options. The most significant part is however being under ''heavy'' penalties to industrial production and expansion that can't be removed until the country is already at war, so there isn't really much to do but passively wait until mid-August 1939. Paradox has acknowledged this and at least tried to go back and alter the focus trees for free to make them better, but most players still aren't impressed. The exception would be Canada, however. After a patch made it possible to fix both Canada's manpower and industry debuffs (they were originally mutually exclusive), Canada is now considered one of the best minor nations to play.
** The Allies in ''II'', as in - the Allied powers. Due to the way the game operates and the requirement to force an alliance to surrender, you will eventually perform a naval invasion on some tiny archipelago in the middle of the Pacific to take out the final British province with victory points, after already taking ''all'' of Africa, Australia and third of Asia first. And you must take down each and every member of the alliance. Needless to say, the Allies are the biggest cluster that can control 3/4 of the map. ''Darkest Hour'' at least introduced events triggering for all the majors and their alliances to surrender after key areas are taken out, but those are scripted - on its own, the AI will just never surrender. Paradox introduced National Unity in ''III'' as a way to address the issue in a more organic way.

** In ''IV'', the Commonwealth countries are generally considered lackluster to due to their focus trees (which were the first DLC ones released with ''Together For Victory'') having aged very poorly in terms of rewards and alternate history options. Paradox has acknowledged this and at least tried to go back and alter the focus trees for free to make them better, but most players still aren't impressed. The exception would be Canada, however. After a patch made it possible to fix both Canada's manpower and industry debuffs (they were originally mutually exclusive), Canada is now considered one of the best minor nations to play.