Game Breaker / X-COM

  • Psicorps in X-COM: UFO Defense. They are hard (and expensive) to acquire, as you need to capture a psi-using alien that is blasting you with said psi-abilities (often straight at the easily affected guy that it can't even see), interrogate the alien, research the tech, build the required buildings, then wait until the month ends for results from said building. If you're extremely lucky, you'll have this by the 4th month, else you might have to wait until the late game aliens show up.

    But it was well worth it. First off, you get to see the Psi-Defense stat of your units, eventually allowing you to get a team entirely immune to psi-attacks. The abilities themselves are powerful as well. The more accurate skill causes the target to panic, making them an easy kill. The other skill is Mind Control, a skill so powerful that you can use it to win the final mission on the first turn single-handedly.
    • Apocalypse nerfed it from merely powerful (the second was merely so hard you actually needed it to win on the higher levels). You can use it to mind-control a zombie, kill it, then you have a pet Chryssalid.
    • And then there's the Blaster Launcher, a weapon that could send a missile out the door of your transport, over the heads of your units, down through the door of the UFO and up the elevator shaft to blow a hole in the otherwise impregnable UFO hull material. Or alternately just take out a Sectopod in one shot. Its successor, the DPT Launcher, was nerfed in a way you can only fire it underwater... unless you consider that you troops can still reaction-fire it! Not to mention that one of the resources necessary to make ammo for it is more abundant in the sequel.
    • Avenger/Leviathan craft. Though the basic interception unit is so weak that every alien craft can outrun it, these two can outrun and outgun even the strongest alien craft - with a bit of a twist: if they survive, they become TOTALLY USELESS for about a month until repairs are done (plus they consume valuable resources to even keep flying). Meanwhile, aliens are happily wreaking havoc...
      • You can actually stick any craft weapon on any ship capable of dogfighting. Cue the Plasma Cannon: not overly powerful or fast, but its range exceeds that of any UFO except the largest Battleships, its ammo is free, and it has plenty of the stuff. And you can order your craft to fire from their maximum combat range, hence making even your lowly Interceptors effectively invulnerable. Battleships are immune to this tactic and do deal massive amounts of damage, but this can be mitigated by attacking them with multiple ships at the same time - the damage gets spread out (dividing repair times amongst the ships present) and the UFO goes down faster (meaning it deals less damage in the first place).
    • Smoke grenades are remarkably effective at decreasing the aliens' initial advantage; just drop it at the foot of the transport's ramp, before leaving, and the chances of the aliens' reaction fire hitting the redshirts drops drastically. Proximity grenades are sworn by for many players to mine UFO exits and buildings aliens might be hiding in. Both together are a potent combination, especially if you've mined a Zombie that turns into a Chrysalid.
    • Running low on money in TFTD? Go into business selling Craft Gauss Cannon. Even after having to pay for the workshop space and technicians and the construction cost, you can make a killing doing this.
      • Ditto Laser Cannons from the first. It's quite useful to build a base filled entirely with working and living facilities, doing nothing but producing and selling them.
  • Not to mention X-COM Apocalypse's Toxigun. A highly powerful weapon that costs just a pair of APs per shot to fire and completely surpasses the aliens' Disruptor Shields. After researching this and the Personal Teleporter, the game pretty much turns into administering point-blank euthanasia shots to the aliens. Even more Alien Gas Grenades and Alien Gas Rockets are available late in the game, provided you manage to capture the Alien Queen live. The Personal Teleporter allows you to instantly teleport your soldiers anywhere on the map, and it is not uncommon to win the mission on the first turn considering that your soldiers are likely people of mass destruction by the time you research this item.
    • Spiritual Successors UFO Aftermath and Aftershock had warp weapons. Subverting the previously established player knowledge of armor=longevity, warp weapons inflict greater damage if the target is wearing armor. Devastating when first encountered, when the weapons are reverse-engineered by the player, they become the single most devastating weapon in the game, capable of one-shot killing anything, as enemies are always wearing heavy armor at that point. Greatly toned down in UFO Afterlight, as the player only gets two warp weapons, with six shots each that can't be recharged during a mission and low base accuracy.
      • UFO Aftershock has psionics with level 3 sniper, using the .50 calibre rifle with accuracy add-on and accuracy boosting psi-gear has a 1.1 - 110% chance of a torso hit. A headshot is merely 100% chance of instantly killing the standard mutant or Wargot. Also you can field a whole team of these girls, and depending on the status of your install the accuracy aura buffs may stack. Gets more insane if you give them Katanas against Wargots in room-to-room combat...
      • Even against enemies that could take multiple headshots and survive, a called shot to the head is considered a critical hit and topples the target over (there are enemies with "knock back resistance" ability but they are not common). Guess how much time it takes to stand up? Approximately same amount as making another called shot. If there is another enemy between sniper and target, then there is chance of hitting the enemy blocking vision, and if this happens, that enemy will be critically hit as if it was intended target of called shot, even if it is impossible to make called shot on that enemy. Very effective against mutants and Starghost combat drones.
      • UFO Aftershock has also short range game breaker. Guns Akimbo. Well developed Cyborg/Ranger/Commando with 2 MP5 SMGs, armour piercing ammo and proper implants has greater range than assault rifles, 10 shot long burst (each shot has individual check for critical hit meaning that at least one critical hit in burst is virtually certain), very low aiming time (if enemy comes from beyond the corner it is possible to kill him before he finishes turning around) and (due to bug) insane movement speed, team him with Human Scout/Ranger/Commando who has much lower range but (even) higher critical hit chance and can spot living target from half the map. That duo can: shred anything into pieces at short range, suppress and outgun anything at medium range, rush from cover to cover so quickly that no enemy can even aim at them and obviously spot targets for snipers. Only drawback: huge ammo consumption.
  • XCOM: Enemy Unknown: Snipers. Oh sweet heavens, snipers. A mid-level sniper with the abilities Squad Sight (lets the entire team do spotting for the sniper) and Damn Good Ground (gives additional bonuses for elevation), when given a skeleton suit or a ghost suit, can just camp out on a high building or object, and pick off enemies as the other party members locate them. As long as there is nothing directly between the sniper and the target, it can be shot, and with better accuracy than the character closer to it. On terror missions, two or three snipers with laser weapons at least and a little elevation can one shot chryssalids (and believe me, you definitely want those down quickly) with a headshot.
    • But wait, there's more: The ability Opportunist removes the aim penalty for overwatch and other reaction shots, and allows reaction fire to score critical hits. This means that if a sniper is on overwatch, and the enemy comes in sight of the sniper (or with Squadsight, any player on the field and there is an open shot between enemy and sniper), it's a much easier and deadlier hit. And then there's In The Zone and Double Tap, the final abilities: In The Zone allows a sniper to take an extra attack if the last shot was made at an uncovered or flanked enemy. Combined with Archangel armor, this can destroy an entire attacking force in one turn, at the risk of your own sniper being out of cover. Double Tap allows a second shot if your sniper doesn't move on his turn. This means your sniper can fire twice if he doesn't move. Once a sniper is in a good position to attack, he no longer needs to move, and on many maps (even the really big ones) it's possible for your sniper to be on one end of the map, and take down with devastating accuracy enemies on the opposite end. Three snipers at Colonel rank with Plasma weapons can fire at least 6 shots a round, with each shot doing enough damage to guaranteedly drop anything less powerful than a Chryssalid with one shot (and they can still land One Hit Kills against those.) Enemies typically travel in groups of three, meaning that unless you get attacked by 2 or more groups at once, you can wipe them all out with shots to spare. If your team is half Snipers, half Assaults, your assaults can track down enemies quickly and your Snipers can pick them off as they are found.
      • Oh, and with In The Zone, this allows you to devastate the most dangerous enemies in the game: Chryssalids, Ethereals, Muton Berserkers, and Sectopods. All four ignore cover, so with a full clip, it's possible to just unload with sniper shots until they die.
    • Squadsight Snipers are fearsome orbital cannons of death once armed with Archangel Armor and Plasma Sniper Rifles, yet the alternative, the Snapshot Sniper, is also a mobile engine of death. With a good suit of Ghost or Archangel Armor, a Snapshooter can mow down cover-ignoring enemies with In The Zone giving them lots of free shots, then take to the air with the Archangel or grapple to a vantage point with the Ghost armor, then they start snap-shooting the now-flanked enemies with more ITZ attacks with their Snapshot accuracy penalty negated by the combination of height advantage, the use of the SCOPE item, and flanking.
      • No longer this in Enemy Within due to the new enemies introduced avert the Complacent Gaming Syndrome. Seekers, specifically, are introduced to kill isolated snipers relying on squadsight.
      • Unless you give them one of the new Gene Mods which shocks them if they try to grab the sniper, or are wearing heavy armor, such as the Archangel suit...which allows a unit to fly and only uses move. Meaning you can fly the Sniper straight up into the air and cover almost the whole battlefield.
      • Rebroken if players realize that Battle Scanners can detect stealth units. Combine that with the Mimetic Skin, toss out a Battle Scanner and the sniper is still in stealth mode while any Seeker will go directly to your squad only to get themselves detected.
      • Or you could just bag all this and double your firepower by sending two Snapshot-equipped snipers in a pair to cover each other. But that's just unfair to the aliens.
      • Or simply have someone accompany the sniper and stay on overwatch.
    • Ghost Armor is the most fearsome suit of armor X-Com has ever produced. Despite its lighter protection than the Titan Armor, it gives a +20 evasion bonus, a passive movement range bonus, plus it comes with a Grappling Hook and 4 charges of invisibility! Being invisible not only prevents Aliens from seeing you, it also gives you a +100 bonus to critical hit rates. Apart from being able to position your squad for perfect ambushes with impunity and no fear of being shot at, your Snipers and Assaults can use the invisibility charges to give them free killer critical hits with their powerful weapons. Enemy Within nerfed the critical hit bonus to +30.
    • Snipers combined with Heavies are flat out unfair against cover-using enemies: Oh, you want to hide behind cover? BOOM!!! Where's your cover now? In pieces on the floor! You can have heavies with rocket launchers devastate anything your opponents are trying to hide behind, opening up a clear shot for your snipers to pick off all of your enemies with In The Zone.
    • With Enemy Within, we now have the MEC Trooper, the single most overpowering thing in the game. Its Minigun will shred virtually any early game enemy it encounters, the Kinetic Strike Module can One Hit Kill anything short of a Cyberdisk, Sectopod or Mechtoid, the Flamethrower is easily one of the best AOE attacks in the game (and has the bonus benefit of spreading the flames further than the Cone intended, as well as panicking anyone hit by it) despite its limited Ammo use, and this is before having a special Class ability. And this is just the Mark I, unupgraded model.
      • That being said, MEC Troopers are designed to be unbelievably powerful in the early game. Conversely, they get upgraded much slower than your normal troops, with fewer weapon choices, no ability to swap out upgrades (i.e. if you get the flamethrower, you cannot get the kinetic strike module without building another MEC suit), and prohibitively expensive costs. You will guard your MEC Troopers religiously because, despite their high initial HP, if they die, you will be out a lot of money and Meld. Mercifully, if a MEC Trooper is KIA, you can still salvage and repair the suit itself, then assign it to a another new MEC operative.
    • Ontop of this, the Training Roulette and Save Scum Second Wave options can easily become this. Save Scum re-seeds the game when you load a saved game, thus allowing you to keep taking your turn until you get the exact result you want. Training Roulette allows for some unholy cross-class combinations - Snipers with Squadsight, HEAT Ammo and Disabling Shot, or Assaults with Close Combat Specialist, Bullet Swarm, Rapid Fire, and HEAT Ammo are possible, and may god help your enemies should he be found to be Psychic or given Gene Mods...
    • Amongst the Gene Mods in Enemy Within, the Mimetic Skin. It's even more effective than the Ghost Armor, an already great armor in the game, as it allows risk-free scouting for your troops. The only thing limiting about it is that the unit must be at full cover and that once they see an enemy and they attempt to move, the enemies will go directly towards opposite directions. The one exception? Snipers (again) thanks to their "Low Profile" perk (or, for that matter, any lucky operative who gets Low Profile due to Training Roulette). In fact, get a Sniper with Snapshot (that did get buffed by negating its penalty aim by -10), go near any cover, and either shoot and kill enemies with the ITZ or set up your other squad mates and wait for the next turn. And it doesn't run out and that unit is still in stealth mode as long as said unit hasn't made a move yet. In fact, they're the better recon team than assaults in this case. Problem with the -10 penalty aim? Just equip a "Scope" to your Snapshot sniper to negate the penalty aim. The only downside is that it costs an ungodly amount of MELD (65 meld + 150 credits for that single augment where the other mods cost less than 35 Meld!) to give to one person thanks to an early patch.
  • XCOM 2:
    • Once you get them to a decent level, Psi Operatives snap the game in half. Their huge range of offensive, defensive and utility abilities allow them to annihilate most enemy units in one turn, and either Dominate or Stasis those they can't. If they manage to get ALL psionic skills, you basically have a soldier that can adapt to ANY situation on the battlefield.
      • Between Fortress and Solace, you will have a Psi Operative utterly immune to any attack that does not inflict direct damage (like melee attacks, gun/beam attacks, and psychic attacks like the Avatar's Null Lance). They will end up immune to disorientation, panicking, mind control, acid, fire, poison, and explosions. Sustain makes sure that they will survive supposedly-fatal injuries by going into Stasis with a single hitpoint, and Soulfire combined with Soul Steal allows them to recover health through a psionic attack that cannot be evaded by organic enemies.
      • You don't even need to do that, as ALL it will take is the right combination of psionic abilities from the Superpower Lottery. An example is the combination of Void Rift, Null Lance, and Soulfire. This gives the Psi Op an AOE attack that can disorient, panic, or outright mind control enemies on the spot, a long range linear, high damage attack, and an Always Accurate Attack that ignores all possible defensive variables. By that point, anything that CAN survive the Psi Op will be easy pickings for the rest of the squad.
    • It's generally agreed that the Grenadier is the most effective starting class, mostly due to how powerful and how useful grenades are in the game. Grenades deal guaranteed damage, shred armor, destroy cover, AND can hit multiple enemies at once. Grenadiers can take skills and upgrades that allow them to shoot grenades farther, carry more grenades, shoot multiple grenades in a single turn, AND deal more damage with grenades. This isn't even getting into the special grenades you can develop like proximity mines, acid grenades, incendiary grenades, gas grenades, and more! Two of their skills make their munitions even more effective - Volatile Mix makes grenades do more damage and have a large splash radius, while Salvo is the Bullet Swarm of the Grenadier, allowing them to take another action after launch if they used their first action to fire a grenade or Heavy Weapon. Due to the synergies, Grenadiers are even more deadly with the heavy weapons used with the E.X.O suits and W.A.R suits, such as Blaster Bombs, Shredderstorm, and the humble Rocket Launcher. Grenades aside, their secondary skillset options are immensely useful as well - Chain Shot is a slightly less-powerful Rapid Fire, Suppression is better that it was in Enemy Unknown (with the larger Aim penalty inflicted by suppression as well as the ability to stack multiple Suppressions from different operatives), Holo-targeting is more effective than in EU, Hail of Bullets guarantees a hit regardless of enemy evasion/cover/defense in exchange for massive ammo consumption, and Rupture is an auto-critical that inflicts the Ruptured debuff on enemies. Such a powerful secondary gunner skilltree allows Grenadiers to continue providing fire support after using all their grenades during an extended mission.
    • The Colonel level skills are ALL this. Considering how hard it is to get a soldier to Colonel due to the Nintendo Hard Anyone Can Die nature of the game, it's probably a case of Purposely Overpowered.
      • For Rangers, Rapid Fire and Reaper. The former is basically taking two shots against an enemy. EXCEPT this time, it has no cooldown, being limited ONLY by the clip size of your soldier's weapon (which can be alleviated with the right upgrades). The latter is a Kill Streak that continues as long as the Ranger gets kills. Sure, every attack in the sequence gets weaker, but with the right set up, (like, oh say a Gunslinger's Faceoff) a Ranger can kill large mobs of enemies in one turn. Add to that the Untouchable perk (if the Ranger gets a kill, the first attack, any attack will have no effect) and the Bladestorm perk (anyone who gets in melee range of the Ranger gets a fistful of sword), and hoo boy, unstoppable killing machine when played right.
      • For Sharpshooters, Serial and Fan Fire. Serial makes every kill made with their primary weapon a free action, effectively making it a RANGED version of Reaper and arguably better than In The Zone from Enemy Within as it even works on enemies in cover, limited only by the clip size and accuracy of your weapon (which can also be alleviated with extended magazines and autoloaders). Fan Fire is Rapid Fire taken Up to Eleven, being 3 pistol shots instead of 2, all of which are counted as a single move, meaning that they have 1 hit chance, and will only cause a reaction from enemies AFTER all the shots connect. Now keep in mind that Special Ammunition stacks with pistol damage from Gunslinger-type Sharpshooters, and you'll see that a Fan Fire burst from a gunslinger with Bluescreen ammo will shred mech enemies. Another Sharpshooter skill, Face-Off, allows them to take potshots at all enemies in range with their pistol, no matter how many of them there are. This skill, when used correctly, will not only allow you soften up multiple pods of enemies at once, but can result in truly mind-blowing numbers of aliens slain with your sidearm in one non-stop chain of pistol shots. There are reported instances of player managing as many as six to nine kills with a single use of Face-Off.
      • Specialists get Restoration or Capacitor Discharge, both skills being upgraded versions of the first skill in their respective trees. Sounds boring? WRONG. Restoration is, in sequence, Stabilize, Revival Protocol and Medical Protocol ON ALL SQUAD MEMBERS IN THE SPECIALIST'S SIGHT RANGE, whilst Capacitor Discharge is Combat Protocol turned AOE with a flashbang thrown in, which can effectively render mobs of enemies impotent, whilst outright killing most robotic enemies.
      • Lastly, Grenadiers get either Saturation Fire or Rupture. Saturation Fire eats up 3 ammo pips in exchange for damaging every enemy and demolishing all cover within it's cone of effect, whilst Rupture is a shot that is a guaranteed critical, as well as applying a Damage-Increasing Debuff to the target. The latter ultimately suffers from the weakness of bad aim, but, again, weapon upgrades can alleviate that weakness.
    • As if that wasn't crazy enough, the Advanced Warfare Systems facility grants soldiers the ability to randomly acquire ANY skill from the other classes, allowing non-Colonel soldiers to get Colonel level skills not meant for their class. Combined with the weapons upgrades and utility weapons and you've got some ridiculous combinations that break the game into a million pieces. A Sniper with Rupture and AR Rounds can One-Hit Kill anything that isn't a full-fledged Sectopod or Gatekeeper, and even then, those two will lose about half their health AND be vulnerable to everything else thrown at them. Additionally, the AWS facility speeds up your soldiers healing rate.
    • The Mimic Beacon in its original incarnation, which can be acquired extremely early in the game. When deployed, it creates a holographic duplicate that enemies will try to attack and then end the next turn. It's intended to only draw in one or two enemy attacks, but due to the fact it can take cover and get defensive buffs, it often results in the entire enemy team taking a break to try (and fail) to kill an obvious dupe. Jake Solomon has compared it to a "get out of jail free" card, and the March 2016 patch removed duplicates' ability to take cover.
    • To lesser extent, the repeater weapon mod. The mod causes any weapon strikes made by the soldier to have a chance to be a One-Hit Kill, with the highest level mod to be 15% chance. This ignores armor or anything else and it works even when the target is a Sectopod, Alien King, or Avatar and even when said hit is a glancing blow from the stock upgrade. In addition, if weapon with a Repeater attached inflicts Poison or Fire damage on an enemy via the specialized ammo types, the lingering damage inflicted by the statuses inflicted by that weapon have additional chances to instantly kill thanks to the Repeater. Yes, this means that that Lancer you hit with Venom Rounds can randomly drop dead at the end of your turn because the poison damage will also work with your Repeater. Firaxis fixed this in an update so Repeaters can only trigger on actual attacks.
    • Introduced in the Alien Hunters DLC is the Frost Grenade, which engulfs its targets in a frosty explosion, freezing them. No enemy is immune, not even the Alien Kings or the Avatars. This can buy the team valuable time to wail on the target, as damage won't undo the freezing (it only expires after a few turns). It can't be reproduced, so it's best used by a Grenadier.
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