History GameBreaker / TurnBasedStrategy

* In the MegaDrive/Genesis port of ''Heroes of Might and Magic: King's Bounty'', you're racing against the clock to defeat all the bad guys and save the king. Luckily, there is a spell called "Time Stop" that briefly freezes time. The Sorceress has many spell slots. The result of using these two together is that you can leisurely sail around picking up money (which always respawns). It also freezes all the random encounters on the map, letting you either easily avoid or only attack the weak ones for easy gold (and possible recruits). Yelling "Za Warudo" while using this exploit is stupid.

** The Necropolis faction, with their dedicated combined artifact and the Hero Thant basically made the game a cakewalk. Thant specializes in Animate Dead, which is the cheaper version of Ressurection, except units are not permanent unless they're undead. Since he specializes in it, he starts with the spell regardless of any other factors. This means that later in the game Thant's army basically suffers zero casualties, especially if it's huge enough to knock out opposing rangers first then pick off enemy units piecemeal. This, combined with the Necropolis's dedicated artifact, which causes Necromancy to not only be buffed by 50% but also raise undead as Liches instead of Skeletons, means that Thant's army grows exponentially with each victory (being able to convert almost 80% of the enemy into liches with zero casualties).

* In ''No Greater Glory'', it is possible for the Union to hold both Charleston and Norfolk on the first turn, even though the Union player was clearly intended by the game designers to lose both. This is especially galling with respect to Charleston, since in real life, there was only a tiny federal garrison of 67 men at Ft. Sumter. Since the game's smallest army increment is 2,000 men, that's how many men the Union starts with in Charleston, with the same number in Norfolk. Normally, the presence of these tiny Union garrisons so inflames local opinion that it provokes spontaneous uprisings of 8,000 men in each area, overwhelming the two garrisons, even though both garrisons are made up of federal army regulars, and therefore are more experienced than the raw levies they are fighting. There's not much you can do to help either garrison as the Union player, however, because on the first turn, you only have enough sealift capability to move 2,000 men, and cannot send any reinforcements into Charleston anyway, because of the blockade. What you can do, however, is pull those 2,000 men out of Charleston, and send them to Norfolk. Without any garrison in Charleston, there won't be any Union presence to provoke an uprising, and the area will remain under Union control! Meanwhile, 4,000 regulars in Norfolk have chance of holding the place. Then, if you can declare martial law in the tidewater region, where Charleston is located, during the next civil affairs phase, you have a chance of holding it, although there certainly will be riots, because, weirdly enough, the game doesn't actually require you to have any troops in a place to impose martial law! And then, of course, in the second strategic movement phase, you can start sending in reinforcements to both areas with newly built transport ships. As such, you can start the game with two of the Confederacy's ports under your control, one of which is one of the Confederacy's major cities, which you need to win, and the other of which is immediately adjacent to Richmond. This fairly simple trick starts the Union off with a ''huge'' advantage.

* In ''JaggedAlliance 2'' fighting at night pretty easy if you have a squad (with the Night Ops skill) and equipment (NVGs and break lights) for it, as enemies have a low field of view, accuracy, a have a tendency to [[ArtificialStupidity run straight at your mercs]] if you attack them from a good enough distance (most likely because they are trying to get in range to counter attack)

* In unpatched ''HeroesOfMightAndMagic V'', the Necromancers were obscenely powerful because of an unfortunate synergy between the fact that their Necromancy skill allowed them to raise a sizable percentage of all living enemy creatures as skeletons, in a game that allowed you to upgrade your skeletons to skeleton ''archers'' on turn 2. Some neutral-monster-bashing later, and you have a stack of archers numbering in the thousands, growing to the tens of thousands, in a game where a single stack of the weakest units numbering 1000 is (supposed to be) a rare event. Cue one-shotting ''anything''. Cue inevitable nerf, by restricting number of creatures raised per week and causing enemy casualties to be raised by creature level. Yes, necromancers were nerfed by allowing them to raise more powerful creatures.
** Which is NOTHING compared to those fucking ghosts from HeroesOfMightAndMagic II. For every unit they kill, a ghost is created. Combined with the large number of wild low level creatures with low defense, building up a 1000+ army of ghosts is very easy. This makes maps where your enemies get ghosts all the more painful since if you lose a single fight against them, their armies can potentially get STRONGER even if you kill all of their other units. I'm looking at you Ghost Planet...
** Demonology and the "Summon Elemental" spells in HeroesOfMightAndMagic IV border on this. Especially if the character with the spell or ability also gets their hands on a [[ArtifactOfDoom Demonary]] or [[AmplifierArtifact Ring of the Elementals]]. Grandmaster Necromancy continued the usual habit of being ridiculously broken by allowing necromancers to raise ''vampires'', which were incredibly dangerous and durable units, allowing the necromancer to create a snowball of fangs and murder as enemy armies were wiped out and added to the growing horde.
*** HeroesOfMightAndMagic IV broke from the mold by making your heroes able to participate in battle themselves. Combat heroes in particular could strike first, strike twice with every attack, take minimal damage from an attack and also be completely immune to magic. With proper spell support, you could give them incredible offensive and defensive abilities to turn them into absolute wrecking balls. Campaign heroes in particular could be carefully herded through academies and stat boosters to accumulate so much power that they could essentially solo maps inside of a month.
** In HeroesOfMightAndMagic III, skills could make or break a hero. Mastery of Earth turned Town Portal into a spell that allowed a character to zoom all over the map, effectively defending every single town you had with one unbeatable army, while mastery of Air let you use Dimension Door and Fly to sequence break your way across the map. Logistics was a vital skill to zip around the map, and a hero that specialized in it was basically an untouchable rocket. Meanwhile, necromancy specialists could amass terrifying hordes, while a hero who specialized in Offense, Defense, or Archery could turn an army into a well-tuned murder machine.

* In ''GalacticCivilizations II'', the Psionic Beam, which does 4 times as much damage as any similar-tech weapon. This is justified by [[EvilIsCool you having to be Evil to get it]], though its use is still frowned upon.

{{Game Breaker}}s in turn-based strategy games. There are seperate pages for ''{{GameBreaker/Civilization}}'', ''{{GameBreaker/Disgaea}}'', ''GameBreaker/FireEmblem'', ''GameBreaker/NintendoWars'', ''GameBreaker/SuperRobotWars'', and ''{{GameBreaker/XCOM}}''.

* Videogames/AdvanceWars has a nasty strategy akin to the memetic ZergRush. On any deployment map you can just keep producing Mech units and swarming your opponent with them. Mechs are strong enough to take on units like tanks and artillery, can cross mountains and rivers, and can capture bases. Best of all, they cost only 3000G to produce each turn. They die fast, but since there are so many of them, your opponent will be overrun and pushed back, allowing you to easily capture their HQ.

* Videogames/AgeOfWonders has some generally nasty units, but the human air galley is generally considered especially so. It has flying, which means that units without ranged attacks or flying are unable to engage it. It's also a flying ballista, which are usually given special consideration by AI when on the ground. It can also transport up to seven other units, giving [[MightyGlacier otherwise slow but powerful]] units a boost and dropping units into places otherwise inaccessible. It also has decent stats and, being a machine, is immune to such effects as fear.

** ''VideoGame/OverWorld'' - in the face of some nerfs, many of ''World's'' best mechs are just about as good as they were in the previous game and it introduces some new ones: The Knight Gundam and the two Musha gundams, all three are close range {{LightningBruiser}}s, though unless you used a promotion code from a Japanese magazine, it'll be a while before you get them. The Unicorn Gundam received some buffs, particularly a move for its NT-D mode that takes advantage of its canon pilot's stats/skills. The Pilot list remains similar though with an universal skill list, only signature skills and stats set apart pilots in their rankings. However with the Master Skill system, Characters such as Code Phoenix, [[spoiler: Aploda and [[BigBad Code Ameras]]]] have special skills that affect more than one unit and with some very powerful effects.

** ''VideoGame/OverWorld'' - in the face of some nerfs, many of ''World's'' best mechs are just about as good as they were in the previous game and it introduces some new ones: The Knight Gundam and the two Musha gundams, all three are close range LightingBruisers, though unless you used a promotion code from a Japanese magazine, it'll be a while before you get them. The Unicorn Gundam received some buffs, particularly a move for its NT-D mode that takes advantage of its canon pilot's stats/skills. The Pilot list remains similar though with an universal skill list, only signature skills and stats set apart pilots in their rankings. However with the Master Skill system, Characters such as Code Phoenix, [[spoiler: Aploda and [[BigBad Code Ameras]]]] have special skills that affect more than one unit and with some very powerful effects.

** The first one is Ellis who just needs to get to level 25 to get her second LimitBreak Regeneration. What it does is that it fully heals all your party members in the screen. Nothing much to it right? What makes her into GameBreaker status is her attack range ''going up to 10'' in a grid where it's at 12 at most! Link her with another character and watch as you slaughter enemies left and right at ''anywhere'' thanks to her range.
** Next is Plum and her second skill Maiden's Prayer which you get as soon as she joins you (she's level 40). What it does is that her skill gives the other party members SP, sacrificing her own. Pump up her SP in the first turn using the other party members, bunch them together, and let loose her LimitBreak. Seeing as you've pumped up the other members by them getting 5 SP per them getting Plum's SP up to 200, they'll reach the 250 SP mark in no time. In which you can [[ThereIsNoKillLikeOverkill destroy enemies left and right.]] You'll only get an A rank at most, but considering the fact that it's a miracle to have a [[RankInflation S Rank]] on bosses, this is pretty much a Godsend.
** Horde all your PP, start a NewGamePlus, and pump up Leonhardt's Strength stat all the way and the only ones you'll have a hard time are the first few battles (and half the time in generation 2 seeing as [[DecoyProtagonist he's not in your party at this point]]) until you get his powerful [[DiscOneNuke Unleash All]].
*** Speaking of which, Unleash All can also be a potent GameBreaker by itself seeing as party members who are down to 25% of their HP will have an ''obscene'' raise of all their stats.
* Due to the game's rather primitive and sometimes crippling AI it is possible to win ''every single'' game in HogsOfWar by poisoning the enemy using a gas grenade and then using the Scout/Commando/Hero technique ''Hide'' to simply wait out the clock. Using this technique you can even defeat the otherwise ridiculously strong Legend class without sustaining hardly any damage whatsoever. Coming in at a close second on the ''crappy game mechanics you can exploit'' bandwagon comes the Spy class ''Pickpocket'' ability. Steal the bazooka or sniper rifle off an enemy Hog and they become near enough completely harmless.

** The Custom Race option can be used to achieve a GameBreaker effect: simply slap both the "subterranean" and "aquatic" bonuses on your custom race. (Never mind that it makes no biological sense whatsoever.) The result: a race that can out-breed any other, given a planet with water. And since most of the easily colonizable planets are "terran" or "aquatic" by default... And more people means more production and science. Plus the subterranean bonus gives a big boost to ground combat when defending against invaders.

** In version 1.2, the Plasma Cannon (specifically, the Heavy Plasma Cannon) was this. Whoever decided to make it that small apparently failed to realize that Enveloping doesn't just mean four times the shield penalty - it means ''four times the damage''. And the Heavy mod largely negates the weapon's worse-than-usual range dissipation. It was entirely possible to lose a late-game battle solely by researching Disruptors and [[ArtificialStupidity having all your bases "upgrade" automatically]]. (In later versions, they [[ObviousRulePatch made the thing 2.5 times as big]], and it was ''still'' in the top class of late-game weapons along with fully tricked-out Phasors, Disruptors, and Gauss Cannons. The difference being that those weapons needed a few levels of refinement to really get good, while the Plasma Cannon was that good as soon as it became available.)

** Black Channel turns a unit into undead; it now no longer needs any upkeep except for one mana, but can't heal. Use this on trolls...who still regenerate. No more massive upkeep, but still healing benefits! (Since undead don't gain XP, you'll want to train your trolls up to elite first, but that's easy enough.)

** ''Knight Of Lodis'' had that any class could equip any weapon. Simple, right? Yeah, but then you've got a ghost that teleports to the target, floats, and uses a hammer. Or you can just use two insanely powerful spears (The second-most powerful weapon (after [[InfinityPlusOneSword the four Snapdragons]]) in the game, [[TheLanceOfLonginus the Spear of Longinus]], is [[CaptainObvious a spear]].) and have your spear-using characters fight each other, hitting the target in the middle twice. (Does not work on Shaher, who stays in the corner.) And then there's SummonMagic...
*** A few more for [=KoL=]: [[InfinityPlusOneSword The four Snapdragons]] are on a completely different plane of existence compared to all your other weapons. You'd be very happy with a weapon of attack 60. Snapdragons: attack 75 right off that bat, and then you can improve that AND give your character stat boosts and special abilities by 'snapping' specific classes and characters. The Ninja and Swordmaster classes are both stupidly overpowered: Ninjas move three times faster than any other character, [[DiskOneNuke are available at the beginning of the game]] and have an insane evasion score. Swordmasters are the same as Ninjas, but trade a tiny bit of speed for the ability to equip any sword in the game, and can cast buffs or status spells. Including Time Stop or Teleport, which are already {{Game Breaker}}s of themselves. Then you have sword techniques that cost a tiny bit of HP to use, but easily allow you to hit the damage cap if you have a Snapdragon... by the end you can beat the last boss with your main character and another (to use TheLanceOfLonginus to break the last boss's invulnerability field). In three turns (one turn to get there and break the field, two turns using of the time-stop special technique combo).
* ''VideoGame/{{Odium}}'' has the Attracting Device. When you deploy it on the ground during battle, monsters become hypnotized and won't attack you, instead trying to reach the device as fast as possible, thus earning you several turns of blasting them to bits without fear of retaliation. Some monsters are immune, but most aren't (including, ridiculously enough, [[spoiler:human enemies]], making several potentially tough fights a doozy.) A fun thing to try is surrounding the device with your men to keep enemies from ever reaching it...

** ''World'' - While there are various good units in the game, a few stand out from the rest: The Halapas Gundam (Think former gamebreaker Phoenix gundam at around its former game breaking level.), [[spoiler: [[TrueFinalBoss Barbatos]], an original mech with nice stats, powerful attacks. And last but not least, Dark History Turn A, which has similar stats to Barbatos, but various broken features and two inexpensive but powerful attacks.]] Though you don't get these until you beat the game. while paling to those three, the 00 Raiser and the 00 Quant are both very good suits with nice stats, attacks and a map wide healing move. In terms of Pilots, you have 0079 Amuro who starts with a skill that raises any white and/or Gundam type mech by up to 25 points; this covers all the best mechs. There's also Movie Setsuna whose skill list is very good (though you won't get him until pretty late in the game) and [[spoiler: Aploda Nuroi, the game's BigGood with the highest starting stats of any pilot and some nice skills]]

*** A few more for KoL: [[InfinityPlusOneSword The four Snapdragons]] are on a completely different plane of existence compared to all your other weapons. You'd be very happy with a weapon of attack 60. Snapdragons: attack 75 right off that bat, and then you can improve that AND give your character stat boosts and special abilities by 'snapping' specific classes and characters. The Ninja and Swordmaster classes are both stupidly overpowered: Ninjas move three times faster than any other character, [[DiskOneNuke are available at the beginning of the game]] and have an insane evasion score. Swordmasters are the same as Ninjas, but trade a tiny bit of speed for the ability to equip any sword in the game, and can cast buffs or status spells. Including Time Stop ([[ExactlyWhatItSaysOnTheTin Stops time for the enemy team]]) or Teleport ([[ExactlyWhatItSaysOnTheTin teleport]]), which are already GameBreakers of themselves. Then you have sword techniques that cost a tiny bit of HP to use, but easily allow you to hit the damage cap if you have a Snapdragon... by the end you can beat the last boss with your main character and another (to use TheLanceOfLonginus to break the last boss's invulnerability field). In three turns (one turn to get there and break the field, two turns using of the time-stop special technique combo).

*** A few more for KoL: [[InfinityPlusOneSword The four Snapdragons]] are on a completely different plane of existence compared to all your other weapons. You'd be very happy with a weapon of attack 60. Snapdragons: attack 75 right off that bat, and then you can improve that AND give your character stat boosts and special abilities by 'snapping' specific classes and characters. The Ninja and Swordmaster classes are both stupidly overpowered: Ninjas move three times faster than any other character, [[DiskOneNuke are available at the beginning of the game]] and have an insane evasion score. Swordmasters are the same as Ninjas, but trade a tiny bit of speed for the ability to equip any sword in the game, and are cast buffs or status spells. Including Time Stop ([[ExactlyWhatItSaysOnTheTin Stops time for the enemy team]]) or Teleport ([[ExactlyWhatItSaysOnTheTin teleport]]), which are already GameBreakers of themselves. Then you have sword techniques that cost a tiny bit of HP to use, but easily allow you to hit the damage cap if you have a Snapdragon... by the end you can beat the last boss with your main character and another (to use TheLanceOfLonginus to break the last boss's invulnerability field). In three turns (one turn to get there and break the field, two turns using of the time-stop special technique combo).

** Then there's Alicia herself: her accuracy and evasion stats are absurd, and the combination of Mysterious Body and [[spoiler:Valkyria]] mean it can be very, very hard to kill her. If you're not worried about how long it takes and leaving the rest of your command-point-bearing officers in the base, Alicia is quite capable of completing several missions by herself.

** Artillery has natural no range dissipation, and Armor Piercing mod: not only armor on the target doesn't matter at all, but its drive usually breaks before hull hit points are gone. Theoretically is negated by Heavy Armor early on. Practically, AI ships almost never has it. So good drives to keep the distance, [[KineticWeaponsAreJustBetter Mass Driver]], 1 more level in Force Fields or 2 for auto-firing, and never mind missing jammers or shields: small mass drivers are good point defence and heavy ones do flat 9 damage, so you can plunder missing tech from crippled and boarded ships with shields up to class V (3-4 [[TechnologyLevels levels]] over such guns).

*** Now promote Karna to the 'Master Monk' class using one of two "Vigor Orbs" found in the game and buy her a pair of knuckles, she is now a very effective front-line fighter as well as a healer, in addition to leveling disgustingly fast. Now consider that you can recruit her and do all of this about halfway thru the game.

** The Kenshin + Natori + Uruza + any monk with convert action is also absurdly unbalanced. Kenshin has a passive skill that lowers all enemies moves by one and boosts her stats. Natori has a spell that, given one turn of preparation, kills 30% of each enemies troops but has the downside of taking up all of her moves. Uruza also has a hit all ability that lowers all moves by one again. The Monk can then use convert action to let Natori and Uruza have multiple uses of their skills.

** In multiplayer mode, forces can be restricted by the number of credits spent in building them. This is fine for [=HERCs=], which have standard equipment costs and never depreciate in value. The [[ArtificialHuman BioDerm pilots]], however, have finite lifespans, and their value is dependent on the number of years they have left to live -- ''not'' on their skills or rank. Through a bit of grinding, it's possible to enter your multiplayer battles with an elite pilot force (with 1 month before everyone's natural deaths), and more credits redirected to better HERC equipment, while still adhering to the same maximum credit restriction as someone with fresh pilots and weaker [=HERCs=]

* In ''JaggedAlliance 2'' fighting at night pretty easy if you have a squad (with the Night Ops skill) and equipment (NVGs and break lights) for it, as enemys have a low field of view, accuracy, a have a tendency to [[ArtificialStupidity run straight at your mercs]] if you attack them from a good enough distance (most likely because they are trying to get in range to counter attack)

** ''Knight Of Lodis'' had that any class could equip any weapon. Simple, right? Yeah, but then you've got a ghost that teleports to the target, floats, and uses a hammer. Or you can just use two insanely powerful spears (The second-most powerful weapon (after [[InfinityPlusOneSword the four Snapdragons]]) in the game, the Spear of Longinus, is [[CaptainObvious a spear]].) and have your spear-using characters fight each other, hitting the target in the middle twice. (Does not work on Shaher, who stays in the corner.) And then there's SummonMagic...
*** A few more for KoL: [[InfinityPlusOneSword The four Snapdragons]] are on a completely different plane of existence compared to all your other weapons. You'd be very happy with a weapon of attack 60. Snapdragons: attack 75 right off that bat, and then you can improve that AND give your character stat boosts and special abilities by 'snapping' specific classes and characters. The Ninja and Swordmaster classes are both stupidly overpowered: Ninjas move three times faster than any other character, [[DiskOneNuke are available at the beginning of the game]] and have an insane evasion score. Swordmasters are the same as Ninjas, but trade a tiny bit of speed for the ability to equip any sword in the game, and are cast buffs or status spells. Including Time Stop ([[ExactlyWhatItSaysOnTheTin Stops time for the enemy team]]) or Teleport ([[ExactlyWhatItSaysOnTheTin teleport]]), which are already GameBreakers of themselves. Then you have sword techniques that cost a tiny bit of HP to use, but easily allow you to hit the damage cap if you have a Snapdragon... by the end you can beat the last boss with your main character and another (to use the Lance of Longinus to break the last boss's invulnerability field). In three turns (one turn to get there and break the field, two turns using of the time-stop special technique combo).

{{Game Breaker}}s in turn-based strategy games. There are seperate pages for ''{{GameBreaker/Civilization}}'', ''{{GameBreaker/Disgaea}}'', ''GameBreaker/FireEmblem'', ''GameBreaker/NintendoWars'', ''GameBreaker/SuperRobotWars'', and ''{{GameBreaker/X-COM}}''.

** ''OverWorld'' - in the face of some nerfs, many of ''World's'' best mechs are just about as good as they were in the previous game and it introduces some new ones: The Knight Gundam and the two Musha gundams, all three are close range LightingBruisers, though unless you used a promotion code from a Japanese magazine, it'll be a while before you get them. The Unicorn Gundam received some buffs, particularly a move for its NT-D mode that takes advantage of its canon pilot's stats/skills. The Pilot list remains similar though with an universal skill list, only signature skills and stats set apart pilots in their rankings. However with the Master Skill system, Characters such as Code Phoenix, [[spoiler: Aploda and [[BigBad Code Ameras]]]] have special skills that affect more than one unit and with some very powerful effects.

{{Game Breaker}}s in turn-based strategy games. There are seperate pages for ''{{GameBreaker/Disgaea}}'', ''GameBreaker/FireEmblem'', ''GameBreaker/NintendoWars'', ''GameBreaker/SuperRobotWars'', and ''{{GameBreaker/X-COM}}''.

* The original ''VideoGame/{{Civilization}}'' had the Pyramids wonder. With just Masonry technology needed to build them, they allow you to change your government at whim, to any type of government (even if you haven't yet researched it), ''without an anarchy period''. That basically allows democracy (a game breaker government all in itself) about 3000 BC. And then, if you ever need to kick someone's butt but the Congress overrules it, just start a revolution, declare war, and continue enjoying benefits of democracy the very next turn! The only thing you need to watch out for is to never study Communism, which disables the Pyramids effect, and luckily, it sits pretty high up in the science tree and you don't really need it.
** The ''Civilization II'' Pyramids were also a game breaker as they counted as a free Granary in EVERY city you have from when you build it (right at the start of the game) right up to the end. What's that mean in real terms? ''Double population growth'' in all cities and it ''never'' expires!
** ''Civilization IV'' still has the Pyramid wonder, with pretty much the same effect - it enables all government civics (''Civ IV'''s equivalent of government types). Combined with stone in one's starting area to halve their cost, this changes them from "hellishly expensive" to "doable", and constructing them gives access to the representation civic, which both allows you to increase the population of your largest cities by around 30-50% for the time period you are in and doubles the research produced by scientists.
** Some of the Unique Units in ''Civilization IV'' also have a vague Game Breaker-esque status. The Incan Quechua is available from the beginning, cheap and cost-effective against archers, making early rushes for the Incas much easier than any other civilization can pull them off. Also, the Roman Praetorian, which is an early Classical Age unit... with an unit strength more common for the Medieval Era.
** ''Civilization II'' gives a number of game breaking wonders, such as Leonardo's Workshop, which upgrades all your units to more modern equivilents when the necessary technology is researched.
** ''Civilization III'' had the Small Wonder "Wall Street". Its effect? Giving you 5% interest on your treasury per turn. After a few turns you had no money issues for the rest of the game, as long as you kept your treasury above zero. It was later fixed with an ObviousRulePatch, capping the generated income from the building to 50 gold.
** In ''Civilization I'', there was supposed to be a major disadvantage to Republic and Democracy: you have to accept any peace offers. But there was a very simple counter: just don't ever meet with representatives from other civilizations. In Civilization II, they tried to eliminate this tactic by allowing a civilization to force a meeting with you any time you move a unit next to one of theirs. Since this ability was exercised most commonly after you take an enemy city, the response to this was to eliminate the defenders from several cities, then take over all of them at once.
** If another civilization is getting ahead of you technologically, you can take over a city (which allows you to steal a tech), move all of your units out of the city, let them take it back, then retake it before they have time to fortify their troops. Rinse, repeat. Add in some tech-stealing diplomats, and you can eliminate several centuries' worth of technological lead in a few turns.
** ''Civilization I'' had a bug that allowed each Settler to perform any one Settler action each turn (some of them were intended to take more than a dozen turns). You could also, strangely enough, build railroads in the middle of the ocean.
** In ''Civilization II'', you can produce unlimited Hides caravans and re-home to a city with high trade. With an advanced civilization, this can result in a new tech each turn, and more money than you'll know what to do with. The game designers apparently tried to prevent this by disallowing re-homing of caravans, but forgot to eliminate it from both menus.
** In ''Civilization II'', having both Railroad and Explosives completely changed warfare. If you had enough Engineers, you could build a railroad across any distance of grassland or plains in a single turn, then use that railroad to transport units across the railroad (all in the same turn). Your artillery only has one movement point? That won't stop you from using it to attack a city a dozen squares away. You can also use a chain of Transports to move a unit across any distance of water in a single turn.
** Also in ''Civilization II'': The UN was a crucial Wonder. Not because it was particularly useful (you could force other civilizations to make peace with you, but that was rather pointless since they'd then just break the treaty a few turns later), but because if another civilization gets it, having them constantly force you to make peace is a hassle.
*** Ironically, holding the UN makes it ''easier'' for a Democracy to wage war. It allows you to bypass the Senate half the time during negotiations, but this in and of itself isn't why you'd want to own it. Rather, the developers programmed the AI to automatically refuse to talk to you if you tried to contact them immediately after taking a city while owning the Wonder. This was intended to keep the player from forcing peace on an AI civ that had just lost territory, but making the effort yourself denied the enemy the chance to force a meeting on unit contact (see above). In effect, you're using two {{Obvious Rule Patch}}es to cancel each other out.
** In Civilization Revolution, the simplified mechanics provides a number of opportunities to completely dominate the AI even on the most difficult setting. And the Leonardo's Workshop wonder is so overpowered, since it upgrades all your existing units. Given the right circumstances, you can destroy any AI. First, always produce as many cheap, weak units as possible. As you're doing this, follow the path on your technology tree to discover the internal combustion engine. Time the building of Leonardo's Workshop so that it occurs right after you discover the engine and gain the ability to build a tank. All those cheap warriors you've been building since the beginning? They're now tanks. The game is over in 2 or 3 rounds max.
** ''Civilization V'' gives us Bushido, the Japanese special ability, which causes units to maintain full defense and attack stats even while wounded. If this wasn't overpowered enough, it's possible to combine this with the Populism social policy, which grants a 25% damage bonus to wounded units. In other words, damaging Japanese units in these conditions ''actually makes them stronger''. However, the effect is less useful in the ''Gods and Kings'' expansion thanks to the changes to the combat system, and is now actually considered slightly underpowered.
** In ''Civilization III'' the Persians are considered by many to be the most powerful civilization in the game because they possess the Industrious and Scientific traits, which grants them bonuses to both production and research. Additionally, their unique unit, the Immortals, are the single most powerful ancient age offensive unit (it isn't until knights come along that a unit possesses more offensive power). The sheer power of the Immortals makes it easy for the Persians to conquer other civilizations during the ancient age and even well into the middle ages.
** If you're going for a conquest victory in ''Civilization II'', the Fundamentalism government type makes taking over the world really easy. Under Fundamentalism you never have any unhappy citizens, and buildings that normally increase happiness instead produce gold (and never require maintenance). You can also produce the Fanatics units, and each city can support up to 8 of them for free. The only downside of Fundamentalism is that scientific research is halved, which isn't a very big deal if you've already researched all the late-game tech or if you're rich enough to just buy technologies from other nations.
** It takes a bit of fine-tuning to pull off correctly, but there exists a strategy in ''Civilization II'' called "Power Democracy" which allows a player with said government to run away with the game. Democracy has two significant bonuses: It boosts trade production on all tiles that already produce multiple trade arrows, and it allows cities with a majority of happy citizens and no unhappy ones to grow by one population point per turn for as long as the people get their BreadAndCircuses. By maximizing luxuries over science and taxes and building the right infrastructure (lots of farms and roads / railroads), you'll eventually hit a positive feedback loop once your cities grow large and productive enough to support full-time specialists who produce income and science independently of the cities' own trade output. Once up and running, you won't need to worry about ''conquering'' continents; you'll be swimming in enough cash for your spies to ''buy'' them outright.
** In ''Civilization V'' Bombers. The fact that they can be stacked while no other units can gives them a huge advantage. The Americans B-52's after being upgraded to Stealth Bombers are an unstoppable force.
** Also in ''Civ V'' The "reduction in gold cost of items" effects, all combined, are very strong in the right hands, as each absolute value adds up with the others instead of multiplying with them. 25% for going 3 social policies into the Commerce branch, 15% for building Big Ben, and 33% for units 2 social policies into the Autocracy branch means a whopping 73% discount for units (would be 58% if the effects multiplied). A civ with a lot of gold in their coffers will be able to pump out a new unit in every city every turn for quite some time, and, with enough cash flow, can keep generating units as needed. And those bombers and stealth bombers from the previous point? Since they stack, you can buy as many of those as you can afford at once, and use them all on the very next turn. However, Autocracy does require entering the Industrial era, so it can't be done early into the game.

** The sequel introduces us to Lash, one of the Black Hole COs. Her ability increases a units offense by 10% for every star of defense a terrain provides it. In other words, parking units on high-defense terrain not only makes them hard to destroy, but they now also pack a nasty punch. Rockets on her HQ annihilate anything that comes near, mechs on mountains can take on medium tanks, and battleships on reefs ''rape everything in sight''. Her CO power actually ''doubles the defense level of all her units as well, which happens to also double their attack bonus, and her CO power fills up rather quickly. She also has no weakness. Even after being Nerfed for Dual Strike, she is still one of the best characters available.

** In version 1.2, the Plasma Cannon (specifically, the Heavy Plasma Cannon) was this. Whoever decided to make it that small apparently failed to realize that Enveloping doesn't just mean four times the shield penalty - it means ''four times the damage''. And the Heavy mod largely negates the weapon's worse-than-usual range dissipation. It was entirely possible to lose a late-game battle solely by researching Disruptors and [[ArtificialStupidity having all your bases "upgrade" automatically]]. (In version 1.31, they [[ObviousRulePatch made the thing 2.5 times as big]], and it was ''still'' approximately tied with a fully tricked-out Phasor as the best beam weapon in the game.)

** ''Civilization V'' gives us Bushido, the Japanese special ability, which causes units to maintain full defense and attack stats even while wounded. If this wasn't overpowered enough, it's possible to combine this with the Populism social policy, which grants a 25% damage bonus to wounded units. In other words, damaging Japanese units in these conditions ''actually makes them stronger''[[hottip:*:Like in anime. xD]]. However, the effect is less useful in the ''Gods and Kings'' expansion thanks to the changes to the combat system, and is now actually considered slightly underpowered.

** Next is Plum and her second skill Maiden's Prayer which you get as soon as she joins you (she's level 40). What it does is that her skill gives the other party members SP, sacrificing her own. Pump up her SP in the first turn using the other party members, bunch them together, and let loose her LimitBreak. Seeing as you've pumped up the other members by them getting 5 SP per them getting Plum's SP up to 200, they'll reach the 250 SP mark in no time. In which you can [[ThereIsNoKillLikeOverkill destroy enemies left and right.]] You'll only get an A rank at most, but considering the fact that it's a miracle to have a [[RankInflation S Rank]] on bosses, this is pretty much a godsend.