The small chainsaw in Dead Rising is nearly legendary for its gamebreaker status. Available fairly early on and then respawning at its original location when used up, this weapon combines one of the fastest attack speeds in the game with one of the highest attack powers. It attacks in broad swings that can wreck large crowds just as easily as single bosses, is one-handed (and thus won't be dropped when switching to another weapon or getting hit), doesn't have to be revved up like its larger cousin, and if the triple-book trick is used to increase its durability, a single small chainsaw can last nearly the entire game. Only a certain few psychopaths even stand a chance against the small chainsaw - no number of zombies are a threat, and most bosses will die in seconds as well.
No boss will survive an encounter with Mega Man's Real Blaster, though acquiring it is a Guide Dang It. It lobs blasts which instagib zombies, three-shot all bosses, and it respawns an unlimited number of times. The blaster has 300 shots and the only limitation is that the player only ever can carry one.
While not quite as broken, the Knife Gloves in Dead Rising 2 are superior to most other available weapons: they generally kill most non-boss enemies in a single hit and do large amounts of damage to bosses, are decently durable, can't be disarmed from you by bosses with the ability to do so and have easily available parts. The drawback is that they could be slightly faster, but this can be somewhat bypassed by their alternate attack.
If you have the Ninja DLC, the Laser Sword becomes this against bosses since the Ninja skillset replaces its normally slow combo with a much faster one, allowing you to remove a good chunk of their health in a few hits thanks to their normally high damage at a much faster rate and at an increased range compared to Knife Gloves. It's still Awesome, but Impractical in most other situations because of the weapon's low durability and the overall lack of convinient flashlight spawn points though.
Books return in Dead Rising 2. One of which is a book on accounting that reduces all store prices by 10%. These books also respawn when you leave and come back, in the same area (I think one exists in the Atlantica Casino, and can be acquired in about three minutes if you know your way around). The kicker here is that you can carry more than ten items if your inventory level is high enough. These books' effects stack. If you carry ten, any item you buy, you won't be charged for (suddenly, the bandit hoodlums don't seem so bad), but you only have one or two spaces remaining. Whoops, time to get more books! (Or get a co-op buddy to take your books, hit a checkpoint, drop them all, then quit to Dashboard, and then come back with duped books.) Suddenly, you're being PAID to buy items. What's this? You want to give me $2000 for this roadster car-key that I can request as many times as I want? Sigh, if you insist!
Eternal Darkness features a magic system centered around a rock-paper-scissors dynamic, with the magic of each god canceling out one of the other gods but being canceled by the third. The player can discover a magical rune of a fourth god, Mantorok, that is more powerful than all of them. An especially notable effect of the Mantorok rune is the ability to make yourself invisible, essentially rendering all non-boss enemy encounters optional.
It also makes "Enchant Item" poison an enemy if you enchant the weapon you strike them with. Mantorok dispels ALL other magicks (you usually have to counter with the right color)...this can be embarrassing if you forget it dispels your invisibility too. Lastly, it also soups up your shield spell to poison any enemies who attack you. Normal shields just repel attacks without damaging the enemy. Truly a game-breaking rune. The game is hard up to Edwin Lindsay's level (the archaeologist...the rune is found in his level) After that, cake, baby!
Easily Eternal Darkness's biggest game breaker of all is the Recover spell. With this spell you can use magik to heal your health and sanity. But since magik is itself regenerated though the simple act of movement, this essentially means this spell grants the player unlimited health and sanity. It makes what would be a challengeing game a piece of cake.
Parasite Eve's Game Breaker is special in two ways. First, it is not possible to have one in the first playthrough. Second, the game does not actually have a single overpowered gun, but features a "weapon modding" systems to allow players with enough time and patience to craft their own personal Infinity+1 Sword. Tools and Super Tools are single-used items that can transfer Stat Bonuses (+ damage, + capacity) or other features (Critical up, Burst fire, etc) from a weapon to another, destroying the original in the process (in case of Tool). These items (especially Supertools) are rare in the first playthrough, so how powerful the player's gun is depends for the most part on how many weapons (and tools) they manage to find and strip the bonuses from. The second playthrough, however, features a brutal Bonus Dungeon, where players can collect Rare Trading Cards to trade for "Tool Kit" (unlimited Tools) and Supertool Kit (unlimited Supertools), and a ton of new weapons with bigger and better bonuses. After piling up stat bonuses on their favorite weapon, players can then supplement it with devastating features, such as more Critical, Command x2 or Command x 3 (allowing you to take 2 or 3 actions each turn), Burst (hit multiple enemies), etc and especially Cyanide rounds (each bullet has a chance to One-Hit KO) ... Also, the gun can be carried over to subsequent playthrough, and thus can be as powerful as the player is willing to spend time to upgrade it. Players can choose their favorite guns based on Base Damage and Range(Rifle), Aiming Time - Time between shots - Time between turns (Pistol or SMG) and number of feature slots available.
Parasite Eve 2 has a cleverly disguised game breaker, which may or may not be intentional. The game is generous with one type of ammo: 9mm parabellum. The critical hit mechanism seems to be this: the lower the firing rate, the higher chance you have at a critical hit. For example, if you want more critical hits, use single shot instead of three round burst for the M93R or M4. However, the "most powerful" weapon in the game is the paltry P8, where 70% of all shots are critical hits. So while the M4 will rack up about 30 damage for a 3 round burst, the P8 will be getting in the neighborhood of 10 per shot on a critical hit. Couple the P8 with the Spartan round, you'll be doing 30 damage.
In the earlier Resident Evil games you could one shot any zombie with the shotgun by using the simple trick of aiming as high as possible and then firing as soon as the zombie was about to lunge. It feels sort of awkward at first and takes a little practice. Once you have the timing down you'll be able to kill the vast majority of the enemies you face and still have piles of shells left over. All the power weapon ammo can be set aside to cheese the bosses and the few stronger enemy types (that would probably represent a much greater threat if ammo was as scarce as it was intended to be). Sadly, this is severely nerfed in the 2002 REmake, where neither the shotgun nor the magnum is guaranteed to behead a zombie in one shot anymore.
In the Resident Evil Remake for the GameCube, using the Grenade Launcher Glitch could give the player unlimited grenade launcher ammo, as all they have to do to get more is repeat the glitch process. This made the entire game ridiculously easy. Well, if you are playing as Jill, that is.
In Resident Evil: Code: Veronica, the knife. Yes, THE KNIFE. In this game, the knife has the interesting property of detecting multiple hits. This allows you to easily attack anything too slow to put you in a Cycle of Hurting. Even Hunters can be easily taken down this way. This means that you can save your ammo for nastier enemies. It's a piece of cake to beat the game this way with handgun or even shotgun ammo in the triple digits.
In Resident Evil 4: The Mercenaries, you have Wesker and Krauser. Wesker has a semi-auto rifle that just kills grunt in one hit, a magnum that two shots most bosses, silenced handgun that leads to melee, tons of grenades and healing. His melee moves tend to kill instantly. His only weakness is that he doesn't have a knife. Krauser has the highest HP, a fast run, an arm that kills everything, arrows that do high damage, good melee, a knife that really hurts, and flash grenades. His weakness? Wesker's just better at killing things.
In Resident Evil 5, it's all about the Weskers. Midnight Wesker is the current score holder. Basically, you shoot grunts in the face to set up for the Cobra Strike, which instantly kills. In Resi5, you get time bonuses for melee, a mere 5 seconds. The top players can chain melee kill after melee kill and basically get infinite time to kill the grunts. And if you run into the boss? Magnum + Melee until the boss dies. And if you gets swarmed, there's always the 5 starting grenades. S.T.A.R.S. Wesker is even stronger, he substitutes the grenades for the HYDRA shotgun, which boasts a range comparable to a sniper rifle with none of damage degrading. He also gets the Samurai Edge, which two shots most grunts. Wesker's weaknesses? No first aid sprays, which the bosses drop.
It isn't all about the Weskers. Tribal Sheva is often considered broken due to her extremely powerful infinite ammo weapon, the Longbow, and her personal boss and mob killer, the Grenade Launcher. Since her primary weapon has infinite ammo, all ammo drops will be for the Grenade Launcher, so she can replace the Nitrogen Rounds with something more effective against the "boss" enemies. Her only real issue is that the Longbow lacks a laser sight and is, therefore, harder to aim than everyone else's weapons.
And with the newest patch and DLC comes the Mercenaries Reunion, the same Mercenaries mode as before but with new characters. One of these is Fairy Tale Sheva, a Sheva that starts out with the Handcannon, the most powerful weapon in the game except for rocket launchers. And to top it all off, she also starts with 5 (5!) Golden Eggs, which fully restore health. Combine this with Online or Offline Co-Op and both using her, and anyone can easily get an S rank on all of the levels. And then theres Heavy Metal Chris with his Infinite Ammo Mini-gun, which is possibly the most broken weapon in the game.
Possibly? There's no hunting for ammo and no need to reload; you can grab several time extensions at the start of the map, and then just camp in a safe place and rack up enormous combos.
Rebecca Chambers. She wields a powerful machine gun, an auto shotgun for close up work and stacks of ammo. What's more, thanks to the crosspad inventory, she can just tap up or down to instan-heal, whichmakessense.
Cryostasis, in its original release, was a tough game, chiefly due to frequent occurrences of That One Boss together with some semi-nerfed weapons, not to mention a non-adjustable difficulty level (example: one boss comes at you with dual, continuous-fire machine guns and more hit points than a medium-sized continent, and all you've likely got is a flare gun, a bolt-action rifle that takes an age of the world to cock and ready between shots, and one sub-machine gun with maybe ten rounds left in it if you've been really careful). When the developers released a patch, among performance increases and the addition of PhysX components, they added a "water cannon," presumably in an effort to rebalance gameplay and also show-off PhysX on the weaponry. This weapon massively breaks the entire game, since it fires continuously without reloading, pins any enemy in place whilst dealing damage and so stops him from firing back, and uses icicles as ammo, which you can find stuck to the walls, floor, ceiling and pretty much everything else in every single area. In short, this patch-applied weapon took a game that was brutally, gruellingly difficult (almost a broken game, in fact, through the sheer difficulty of beating some of its overpowered enemies using only slow-firing weapons with a chronic shortage of ammo), and swung it ridiculously far in the other direction, making it almost insultingly easy.
If you're willing to pony up a measly $4, you can utterly break the original Dead Space by downloading the Advanced Unitology Suit, which is not available in the normal game. The suit itself is heavily reinforced and features 60% damage resistance, which is twice as much as the next most-powerful suits (the Scorpion and Astro Suits, which are DLC releases). It makes the post-game unlockable Military Suit look like a joke, and it comes included with three extra weapons that deal more damage than their original counterparts. It essentially turns the game into a cakewalk, as players will be able to stand around and let Necromorphs whale on them for extended periods of time, rendering the entire "survival" part pretty much trivial... and don't forget, you can access this DLC content right at the beginning of the game. Have fun.
To a lesser extent, the console-exclusive armours (Obsidian and Elite for PS3 and Xbox 360, respectively) would net you a suit with inventory space equivalent to the end-game suits (though lesser armour protection) for a measly $1.50. What truly made it game-breaking was that they were free for the first few months following release.
In Dead Space 3, the demo reveals a rather potent game breaker if you fool with the weapon crafting for a bit. Take a large weapon frame, and place on the top a military component, with the tip that allows for fully automatic fire. On the bottom, place the survey charge, with the tip that converts it into a rocket launcher. On the top add-on, place the component that prevents you from being harmed by your explosions, at the bottom add-on the part that improves explosives. Now, in the chips, place 4 +2 attack chips on top. On the bottom, place 4 +2 Clip Size chips. You now have a weapon that has as a primary attack a rapid fire, high clip size attack that does insane damage with high precision, and the bottom can shoot 3 rockets without reloading. Depending one how quickly you can make this in the full game, this may either be a massive game breaker, or an Infinity+1 Sword. Either way, happy hunting.
The telemetry spike with a tip to change it into a chain gun and a force gun on the bottom is a nearly unbeatable combo. While it lacks the perfect accuracy of a pulse rifle or seeker rifle, its rate of fire means it does more damage in the same amount of time, and unless you are trying for head shots on humans, you don't NEED perfect accuracy, as most distant targets (like boss weak points) are large enough that nearly all shots will hit anyways. The force gun will allow you to knock back any enemy who gets too close, or any group that tries to mob you to death (Feeders, being incredibly weak, will often die from a force blast if it has an elemental add-on effect to it), and you can then open fire with the chain gun. With chips to boost clip size and damage, you can body shot to death most enemies in less than a second, and if you aim for the legs first, then you can accelerate the process, as their bodies will drop into to bullet spray once their legs go out. You can save the rocket launcher for the bosses. In new game plus, with +3 chips available, this weapon can take out entire attacking waves without the need to reload.
The military engine + precision tip = the Seeker Rifle. A semi-auto sniper rifle in a game that requires you to dismember jittery opponents doesn't seem appealing, but it more than compensates for its slow fire rate and clip in terms of pure, raw damage. The default weapon can kill most enemies in two hits, regardless of dismemberment, and with the later-game damage upgrades, you just need to hit somewhere vaguely on their body to send them ragdolling. Granted, you shoulld probably take another weapon against smaller, swarming enemies, but against any human-sized or larger enemy, this weapon is an OHKO.
The Shish-Ka-Boom: A telemetry spike default tip combined with a detonator module. The primary attack impales the enemy and knocks him back. Then, trigger the detonator, and BOOM! The enemy is torn apart by the explosion, damaging any enemies unfortunate enough to be nearby. While the detonator has a low clip size, this weapon is highly effective against humanoid enemies, and can often take out both the target and any enemies that were standing behind him when you trigger the blast. Combine with a safety guard and an explosion amplifier, and you have officially redefined the term "Boom-stick".
The Crush Lens from Fatal Frame II, which one-shots pretty much every ghost in the game, even on Hard mode.
On Dead Island, Sam B and blunt weapons. The reason why is simple: all weapons have the Force attribute, which basically determines how much stamina damage is done with a hit. If an enemy runs out of stamina, they fall down. If a downed enemy is hit, force is transformed into damage. Sam B, the blunt weapons specialist, gets huge boosts to blunt weapons force and damage. Here's the breaker, though: blunt weapons break bones when targeted on enemy limbs, and since enemies don't have a crawl animation, a broken leg is an instant kill. Use kicks and attacks to knock an enemy down, then swing once on the leg, and it's an instant kill. While this is less effective on living enemies and any zombie brute level or higher, this skill allows you to easily wipe the floor with walkers and infected, which are far more common, the only drawback being that the high force and long range blunt weapons like the Sledgehammer or the Wrench tend to be really slow and drain a lot of stamina.
Or if you see or hear them then jump up onto a car. Walkers and infected typically cannot touch you there (typically, a lucky strike or rush might do it) allowing you to crouch with anything the size of a sickle or bigger. Best seen in the Quarantine Zone, doing this causes the infected to completely flip and spawn em masse, leading to some easy kills.
The unlockable Unlimited Sub Machine Gun in Silent Hill 3. Yes, you read that correctly. You can getUnlimitedSub Machine Gun. Every last regular enemy is helpless before it; the SMG hit-stuns them, and with the unlimited ammo you can rat-a-tat-tat-tat-tat away 'til they drop. Even some BOSSES are made laughable by it.
In the STALKER games, the 9x39 millimeter Vintar BC and SA Avalanche. The former is a silenced sniper rifle (the real-life VSS Vintorez) and the latter is a silenced assault rifle. They're mid- to late-game weapons in the first game (although it can be obtained about a third of the way through the game), but in the latter two they can be obtained within an hour of starting a new file. The main difference between the two is slightly better accuracy and damage for the Vintar at the cost of reduced magazine size (10 rounds instead of 20) and increased weight. In Call of Pripyat, the Avalanche can have a scope mounted, making it a roughly equal substitute for the Vintar. Both of them hit like a truck and can one-hit-kill any enemy with a headshot from an absurd distance once you adjust to their use, to the point that a group of bandits around a campfire won't react when one of their buddies suddenly drops dead. The ammo is relatively heavy, but with the amount of damage that it deals out you won't need nearly as much. Both weapons are also equally useful up close, making it simple to use the Vintar as a hellishly powerful battle rifle.
Another breaker (crossing over with Disc One Nuke) is the Tunder assault rifle, the fictional counterpart to the OTs-14 Groza. Normally chambered for 9x39 millimeter like the Avalanche and Vintar, a unique version exists that is chambered for the incredibly common 5.45 millimeter (the common AK round you'll see thousands of over the course of a single game) but still does the damage of a 9x39 millimeter, allowing you to hit far above your weight class at that point. It occasionally spawns in the starting vendor's inventory, allowing you to buy it if you scrounge enough cash very early on and set yourself for weapons for the first half of the game. If it doesn't spawn in Sidorovich's inventory, it can be found on a Duty member. If you aren't willing to piss off Duty to get it, just wait for the environment to kill him off and loot his corpse.