History GameBreaker / Stellaris

* The Overtuned origin allows your empire to choose a selection of overtuned traits, which grant massive bonus at the cost of reducing your leader lifespan (which has become very important). However, there is nothing stopping you from picking venerable and enduring to cancel out the lifespan malus from these traits, with most taking only away 10 years while enduring alone gives you back 20. What's more, the bonus from these traits far outstrip the malus from negative traits, allowing you to do things like get a 20% net pop growth rate if you take Pre-planned Growth (30% bonus growth rate for minus 2 trait points) alongside Slow Breed (10% malus growth rate for plus two trait points).

* Slavery has stubbornly resisted attempts to balance it. From 1.8 onwards, Slaves produce massive amount of unrest, but that is easily fixed with a ''Slave Processing Plant'' and a sufficient amount of Defense Armies, which are cheap as dirt in the first place. In return, you get a Mineral production bonus that can go as high 45%[[note]]Chattel Slavery (10%), Artificial Moral Codes tech (5%), Slave Processing Facility (10%), Slaver Guilds Civic (10%), Iron Fist trait on the governor (10%)[[/note]] ''before'' adding in the general bonuses; to contrast, non-slavers can only get up to +20% from free pops' happiness, and they'll rarely achieve even that. A fairly advanced empire with a mineral-focused build can raise this to up to 90%[[note]]using a Mineral Processing Plant II (20%), the Industrious species trait on the enslaved (15%), and the Mining Guilds civic (10%)[[/note]], enough bonus to boost your Mining Facilities' productivity to [[HigherTechSpecies Fallen Empire]] level, if not more, as FE Mineral production buildings cannot be operated by Slaves. And Slaves are forced under ''Impoverished Conditions'', thus reducing Consumer Goods cost. And you get to recruit the [[BattleThralls Slave Armies]], the perfect disposable fodder for throwing in [[ZergRush cheap waves]] at your enemy, as a cherry on top. This trait could further be combined with the "Syncretic Evolution" trait, which lets you start off with an obedient SlaveRace, boosting mineral production by ''another'' 10% while reducing unrest even further. Starting in version 2.2, Slavery is more restricted -- players must pick the Slaver Guilds Civic to use it at all, and Authoritarians aren't automatically inclined towards slavery. Additionally, the Slaver Guilds and Syncretic Evolution civics became mutually exclusive, prevent players from stacking their additive bonuses.

* Machine Empires in 2.2 until 3.0 were beyond absurd.
** First off, Machine Empires totally ignore habitability, which is now a significant stumbling block for all other empires. A low habitability world is a significant drain on its worker's productivity, which Machine Empires do not have to pay attention to.
** Beyond being able to colonize anywhere, the way machine populations spread is different compared to biological pop units. Machine pops have to be built (requiring special jobs that use minerals to proceed) but go significantly faster than biological pops at pretty much every stage of the game. Combining the two allows for Machine Empires to snowball very rapidly.
** Driven Assimilators also gain the growth speed of their cyborg drones, which can drive their growth rates to even more absurd levels. This was nerfed in 2.3 by making Assimilators have less free population building jobs and giving Cyborgs a hefty negative to pop growth, but they still grow very fast, even for machine empires, who already grow extremely fast.
** Both Assimilators and Exterminators also have the ''Total War'' Casus Belli, which allows them to ignore the claim system outright and go to war with anyone at any time. This includes automatic and instantaneous transfer of any systems they take over, at the cost of instantly losing any systems they lose control over.
** And of course, two of the three "special" Machine Empires instantly start doing something to biological populations they control. Assimilators immediately begin turning them into Cyborg Drones that have no free will -- meaning that an Assimilator at war will have unheard of pop "growth," and Exterminators immediately begin breaking the populations down to energy, supercharging their economy.
** Non-Servitor Machine empires have a simplified economy since they don't have to worry about Food, Trade, or Consumer Goods. While this leads to a less-efficient use of materials compared to an organic empire it more than makes up for it with a machine empire's very efficient use of districts, building tiles, and population, allowing them to produce ''much'' more than those material inefficiencies cost them.

** Similarly, the tech scaling versus sheer quantity problem extended to ground armies, which had to be manually built if you wanted anti-rush defenses. Defensive armies are about twice as strong as typical Assault armies, but while a planet's defenders had limited slots for units (maxing at 25), attackers could drop doomstacks of ''hundreds'' of units (typically, Clone Armies) that could ''all'' attack at once. Defenders of any strength or fortification would get overwhelmed, allowing players to completely bypass fortification/bombardment/army strength rules and rendering planetary shields a TierInducedScrappy technology. The fix was to restrict the number of units that could attack ''or'' defend at one time (turning a slaughter into a Thermopylae situation), and meanwhile abolishing manual defensive armies -- planets now automatically spawn their own defensive armies to stop rushes, add defender's advantage for free without manually-bought troops, and HoldTheLine until reinforcements arrive. The relative strength of defensive armies meant that one-on-one, it's nearly impossible to wear down planets of equal troop strength unless players follow bombardment rules and kill off defenders.

* [[https://www.youtube.com/watch?v=EBxdkxXGmms Fortress Worlds]], a planet filled with nothing but Fortresses and a Planetary Shield Generator. Placed on a chokepoint, the planet will be a ''massive'' roadblock to anyone invading your territory, as the FTL Inhibition prevents them from going anywhere, and they ''have'' to capture the planet first. Yeah, good luck doing that with the 4,000 Garrison strength (for context, an army of 1000 is considered large) and the 75% reduced effect of Bombardment. It will take literally ''years'' for the invading force to get past the roadblock, giving you ample time to launch a counterattack. That is, unless the attacker throws up their hands and [[AlwaysABiggerFish unleashes a colossus]]...

* The metagame has shifted considerably in the 2.0 update. The most powerful early-game weapon? Torpedoes. They can be acquired relatively early, and they deal massive damage that bypasses shields and deals double damage to armor. Against other ships in early-game, most of which have either a low amount of point defenses, or rely on shields and armor, a volley of torpedoes can deal massive damage before the battle even starts, coupled with the new disengagement mechanic (ships may leave combat at a certain health percentage) and ships dealing less damage the more damaged they are, they can single-handedly steamroll empires until better point defenses are acquired. Worse still, you can put them on corvettes the moment you get them, which means you can field them in sufficient numbers to overwhelm even initial uses of point defense, and the Missile Boat hull option includes an S slot, perfect for adding a shield-shredding Autocannon to compliment the torpedo when the ship enters knife-fight range, which then starts shredding the hull once the torpedo has eaten through all the armor.
** The 2.0 disengagement mechanic and the new war exhaustion mechanics mean that Torpedo Corvettes have become something of a GlassCannon as losses result in war exhaustion. The surprise winner of these new mechanics? ''Battleships''. Disengagements don't incur exhaustion, battleships still have their same-old mammothian defensive stats, and the AwesomeButImpractical note on the main page can still be rendered moot by having a fleet full of Battleships. Thus, the only two ship types arguably worth making at all are Corvettes for speed, and Battleships for sheer cost-efficiency.

* Playing as Driven Assimilators is perhaps the most broken playstyle, as it makes full use of UnstableEquilibrium through VictorGainsLosersPowers. Unlike normal empires, conquered populace won't be discontent and rebel against your rule; instead, they get plugged into the gestalt consciousness, eliminating all desire to rebel. Unlike genocidal empires, you don't need to repopulate the conquered planet; the original population are still there, only plugged into the network. And if you feel the process is still too slow, there's the Nanobot Dispersal to instantly convert the entire planet's population to your cause. There's snowballing, and there's ''this''.

** Non-Servitor Machine empires have a simplified economy since they don't have to worry about Food, Trade, or Consumer Goods. While this leads to a less-efficient use of materials compared to an organic empire it more than makes up for it with a machine empire's very efficient use of districts, bui

** In patch 3.0 "dick" as population growth was reworked, while still not "bad" per se. the current meta leans towards raw population growth factor (biological ascension and evolutionary mastery allow for the fertile trait giving a whole 40% boost). The fact that cloning vats have been reworked to allow parallel pop growth on planets and the shift in industrial focus being districts instead of population have finally knocked it down a few pegs.lding tiles, and population, allowing them to produce ''much'' more than those material inefficiencies cost them.

* Mastery of Nature and Enigmatic Technology have become the most useful ascension perks in the game. Mastery of Nature allows you to increase the tile count of a planet based on how small it is, making it useful for colonizing planets, while Enigmatic Technology gives you a sensor range boost and forbids other empires from reverse-engineering your technology, meaning that any unique technology you discover, including jump drives, space monster debris, or leviathan-only components, will be only yours without any risk of other empires gaining your edge. Mastery of Nature remains strong in the 2.2 update since it adds two more Districts instead of a few tiles, regardless of planet size, but its cost is much higher. Enigmatic Technology was nerfed by patch 3.0 by changing the sensor range (very useful) to an encryption bonus (prevents being spied on, which the AI rarely does) and making it a perk heavily weighted towards multiplayer.
* Technocracy gives +1 Unity ''per researcher''. Unlike priests under Exalted Priesthood, there's no limit to the number of researchers allowed on a given planet, which allows Materialists to build unity as fast as Spiritualists (who specialize in the subject). This was nerfed slightly as it's now only available to Fanatic Materialists but is still considered one of the best civics available.

* Machine Empires in 2.2 to current are beyond absurd.
** First off, Machine Empires totally ignore habitability, which is now a significant stumbling block for all other empires. A low habitability world is a significant drain on its worker's productivity, which Machine Empires do not have to pay attention to.
** Beyond being able to colonize anywhere, the way machine populations spread is different compared to biological pop units. Machine pops have to be built (requiring special jobs that use minerals to proceed) but go significantly faster than biological pops at pretty much every stage of the game. Combining the two allows for Machine Empires to snowball very rapidly.
** Driven Assimilators also gain the growth speed of their cyborg drones, which can drive their growth rates to even more absurd levels. This was nerfed in 2.3 by making Assimilators have less free population building jobs and giving Cyborgs a hefty negative to pop growth, but they still grow very fast, even for machine empires, who already grow extremely fast.
** Both Assimilators and Exterminators also have the ''Total War'' Casus Belli, which allows them to ignore the claim system outright and go to war with anyone at any time. This includes automatic and instantaneous transfer of any systems they take over, at the cost of instantly losing any systems they lose control over.
** And of course, two of the three "special" Machine Empires instantly start doing something to biological populations they control. Assimilators immediately begin turning them into Cyborg Drones that have no free will -- meaning that an Assimilator at war will have unheard of pop "growth," and Exterminators immediately begin breaking the populations down to energy, supercharging their economy.
** Non-Servitor Machine empires have a simplified economy since they don't have to worry about Food, Trade, or Consumer Goods. While this leads to a less-efficient use of materials compared to an organic empire it more than makes up for it with a machine empire's very efficient use of districts, building tiles, and population, allowing them to produce ''much'' more than those material inefficiencies cost them.

** Shattered Ring and Void Dwellers are also extremely strong choices. The former starts you on a segment of a Ringworld, with two other segments you can repair with the right technology, and an irrepairable segment next to a cracked planet that gives you +20 Minerals; perfect conditions for a tall, science-based Empire (granted, those kinds aren't the beasts they used to be). Void Dwellers gives you three Habitats orbiting a shattered planet, with a small bonus to food production on them and the technology to make more; more suited to an industrial/population-centred Empire, and you can get alien pops to colonise the worlds you don't need (and later genemod your native species so they can live on planets anyway).
* Synthetic Ascension continues to float in and out of game-breaking status. Taking it lets you turn your biological pops into robots, which confers most of the benefits of a machine race (immortal leaders, ignoring habitability, no need for Food, high pop growth) with most of the benefits of a biological race (government ethics, faction Influence gain, better civics, Happiness production bonuses, less crime/deviancy) all while also giving a large bonus to production of almost everything and giving special traits to synthetic leaders that increase those bonuses even more, making your synthetically-ascended race better at being machines than machine races. This also doesn't affect any other races in your empire unless you specifically say so, meaning you get the benefits of fast organic ''and'' fast mechanical pop growth, giving you ''ludicrous'' growth rates. It's generally accepted that any race that can take this should take it, with roleplay and a few specific gimmick builds being the only reasons not to.
** In patch 3.0 "dick" as population growth was reworked, while still not "bad" per se. the current meta leans towards raw population growth factor (biological ascension and evolutionary mastery allow for the fertile trait giving a whole 40% boost). The fact that cloning vats have been reworked to allow parallel pop growth on planets and the shift in industrial focus being districts instead of population have finally knocked it down a few pegs.

** With the addition of Indentured Servitude as a type of slavery, it's broken again. All those slavery production bonuses? Go to Indentured Servitude and you get those bonuses to ''specialist'' jobs, like research and alloy production. It's considered the best type of slavery to use for this reason.

* [[https://www.youtube.com/watch?v=EBxdkxXGmms Fortress Worlds]], a planet filled with nothing but Fortresses and a Planetary Shield Generator. Placed on a chokepoint, the planet will be a ''massive'' roadblock to anyone invading your territory, as the FTL Inhibition prevents them from going anywhere, and they ''have'' to capture the planet first. Yeah, good luck doing that with the 4,000 Garrison strength and the 75% reduced effect of Bombardment. It will take literally ''years'' for the invading force to get past the roadblock, giving you ample time to launch a counterattack. That is, unless the attacker throws up their hands and [[AlwaysABiggerFish unleashes a colossus]]...

* Mastery of Nature and Enigmatic Technology have become the most useful ascension perks in the game. Mastery of Nature allows you to increase the tile count of a planet based on how small it is, making it useful for colonizing planets, while Enigmatic Technology gives you a sensor range boost and forbids other empires from reverse-engineering your technology, meaning that any unique technology you discover, including jump drives, space monster debris, or leviathan-only components, will be only yours without any risk of other empires gaining your edge. Mastery of Nature remains strong in the 2.2 update since it adds two more Districts instead of a few tiles, regardless of planet size, but its cost is much higher.

** And of course, all three of the "special" Machine Empires instantly start doing something to biological populations they control. Servitors put them into habitats immediately after the war for massive unity bonuses while also making it unlikely they will ever rebel, Assimilators immediately begin turning them into Cyborg Drones that have no free will -- meaning that an Assimilator at war will have unheard of pop "growth," and Exterminators immediately begin breaking the populations down to energy, supercharging their economy.
** Machine empires have a simplified economy since they don't have to worry about Food, Trade, or Consumer Goods. While this leads to a less-efficient use of materials compared to an organic empire it more than makes up for it with a machine empire's very efficient use of districts, building tiles, and population, allowing them to produce ''much'' more than those material inefficiencies cost them.

* Combo of Nihilistic Aquisition ascention perk and one-planet playstile. Although it leans into [[DifficultButAwesome Difficult but Awesome]] area and is [[VideoGameCrueltyPotential quite cruel]] in nature, if played right it can be extreamly broken. Two options are used in particular:
** The first one is based on building a superior fleet early on, stealing pops from your enemies non-stop by being constatly in war with someone and using them as a disposable supply for the forced labor. It allows to get even more broken economy than general slavery and for lesser cost.
** The second one is based on the Utopian Abudity living standard. Most of your people just do nothing and generate unity and science by doing nothing. Yes, they have nothing to eat, sometimes nowhere to live and no consumer goods to get, but who cares. And you just add more and more of them by stealing pops from other planets. Yes, you have to base you mineral and energy production on the space stations only and have to use a lot of military force to keep the order. But it is a low price to pay as you have a perfect defence on your capital, can spend a lot of building slots to the alloys production and have a total unity and research domination.

* Synthetic Ascension continues to float in and out of game-breaking status. Taking it lets you turn your biological pops into robots, which confers most of the benefits of a machine race (immortal leaders, ignoring habitability, no need for Food, high pop growth) with most of the benefits of a biological race (government ethics, faction Influence gain, better civics, Happiness production bonuses, less crime/deviancy) all while also giving a large bonus to production of almost everything and giving special traits to synthetic leaders that increase those bonuses even more, making your synthetically-ascended race better at being machines than machine races. It's generally accepted that any race that can take this should take it, with roleplay being the only reason not to.

* Synthetic Ascension for empires turns your species into a synthetic race with very good micro-managing options, with bonuses across the board, and the most important part being that you can colonize ANY habitable planet, and you no longer need food, allowing you to replace your farms with other buildings.

** Shattered Ring and Void Dwellers are also extremely strong choices. The former starts you on a segment of a Ringworld, with two other segments you can repair with the right technology, and an irrepairable segment next to a cracked planet that gives you +20 Minerals; perfect conditions for a tall, science-based Empire (granted, those kinds aren't the beasts they used to be). Void Dwellers gives you three Habitats orbiting a shattered planet, with a small bonus to food production on them and the technology to make more; more suited to an industrial/population-centred Empire, and you can get alien pops to colonise the worlds you don't need (and later genemod your native species so they can live on planets anyway).