[[folder:Fallout 1 and 2]]
* If your Gambling Skill is at 100% or higher, you almost can't lose at roulette if you keep placing low bets (about $2). All you need to do is to hold down the hotkey '1' in the dialogue at the table and wait until you're in the millions. Since everyone except the casinos have limited resources, the whole wasteland economy is somewhat broken.
* Even with a pitiful Barter skill level, other people's goods will be worth substantially less than yours. Thus, with a bit of swapping back and forth ''you can take everything a person is willing to sell you for free''. Later games fixed this by jacking up the merchants' selling prices so that even with a maxed Barter skill you still pay through the nose for items. However in all games it's possible to shoot the merchant in the face and take all their items for free - sometimes without even being attacked by guards for doing so!
* The title you gain after becoming the New Reno boxing champion reduces normal damage (anything except laser, plasma, fire, explosives, electrical and EMP) by 12 points, which adds to any armor you wear. The calculation is made for each bullet (you can get hit without armor by a minigun blast ''for no damage''), and the only endgame enemies who use laser or plasma are non-military personnel (low HP and no armor) and the end boss.
* Abilities that reduce the AP cost of attacks are seriously unbalanced. The Fast Shot trait reduces the AP cost of all attacks by 1[[note]]In ''Fallout 1'' at least, ''Fallout 2'' gives you no bonuses[[/note]], but prevents the character from making aimed attacks. Combine this with perks that also reduce attack AP cost, and by the time you're around level ten, a turbo plasma rifle whose shots cost 2 AP, and super sledge attacks only for 1. With a high Agility you can do 200+ damage per turn with no special preparation, which is enough to kill everything but a few bosses in one turn, or shred groups of super mutants.
* The Bozar in ''Fallout 2'' has the power of a minigun, the accuracy of an assault rifle, and an ammo type which is cheap to purchase, light-weight, with -20% Armour Class and damage modifier (means the target is more likely to get hit and take more damage) and sold in bulk just about everywhere. This makes it probably the ultimate weapon in-game. A group of shop guards you can meet fairly early on have the gun conveniently unequipped in their inventory. All of them are unusually easy to steal from, even with no points in the Steal skill. Commandeer two of these guns and stick them on a character with a decent skill in Big Guns and you have more than enough firepower to last throughout the rest of the game.
* Also in ''Fallout 2'', with a bit of saving and luck you can run straight to Navarro base, which contains the second best armor in the game, for free. And you don't even need to kill anyone... Since it gives a +4 Strength bonus, this is completely ridiculous.
** Not to mention all the lockers around filled with the good stuff and insane (at least for early game) amount of experience granted for quests around the base. [[FanNickname The Navarro Run]] made as the first thing after leaving Arroyo can grant you at least 5 levels, second best armour (the best one is in TheVeryDefinitelyFinalDungeon), powerful weapons, more ammo and equipment than you can carry and all you have to do is go there. Optionally you can also kill (without any repercussions) the resident MadScientist in a soundproofed room, which gives you access to even more XP and one of the best [=NPCs=]. After the Navarro Run the game is so broken that all the early quests are not only hardly profitable, but simply boring.
* By knowing where to look and a small amount of reloading, a character can go from 6 points of luck to 10. Combine this with Finesse and you get a total critical chance that will likely exceed 20%. Add in a P90 (every bullet can score a critical, every critical will have a HIGH chance to instantly kill a target) and the game is over barring a few more hours of mouse clicking. Being aware of the ways to boost statistics in this game also means you can get 10 ability points in EVERY SKILL when factoring in item bonuses.
** As in ''Fallout 2'', you can raise your stats during the gameplay by 19 points like this:
*** Strength by 6
*** Perception by 2
*** Endurance by 1
*** Charisma by 3
*** Intelligence by 3
*** Agility by 1
*** Luck by 3
** Speaking of statistics, a player can have one companion for every 2 point of Charisma rounded down. The check for this is based on your CURRENT charisma score instead of your actual one. This means that by tripping on Mentats, a character so dumb they cannot normally understand human speech can have a loyal following of five lethally powerful companions who fill out all his/her dump stats and leave them with barely enough living enemies at the end of the first combat round of any encounter to get a punch in.
* In Fallout 2, maxing out your luck at 10, and getting the Jinxed trait causes the trait to basically rarely affect you. Use only unarmed combat, and watch as enemies guns explode in their hands with every shot and they cripple their own limbs trying to punch you, making the game ''ridiculously'' easy.

[[folder:Fallout 3]]
[[AC:Main game]]
* The friendly and intelligent Super Mutant Fawkes, whom you can rescue in the main questline. Later, he can team up with you if you have good Karma. He is [[NighInvulnerability Nigh-Invulnerable]], wields an incredibly powerful [[GatlingGood gatling]] [[BeamSpam laser]], and he steals so many kills that most players have to fire him until and unless they've hit the level cap.
* The Grim Reaper's Sprint perk restores all AP if you kill an enemy in VATS. Now consider that with decent stats it's ridiculously easy to kill at least one enemy in each VATS cycle; also consider that while VATS lasts you're effectively invulnerable. Keep hitting the VATS key/button as you exit it, and you'll slaughter every enemy in range while scarcely receiving any damage yourself. This perk was so gamebreaking in ''3'' that it was heavily nerfed in ''Fallout 4'' along with VATS in general - time won't be frozen and you instead get 75% the usual damage.
* There's a setup that turns every single standard attack into a critical hit. Deathclaw Gauntlets do 20 damage per hit, a critical hit gives an additional 30 damage. As previously mentioned, they ignore armor, so they'll always do the full critical damage every single hit.
* The Dart Gun. The weapon itself doesn't do much damage, but it does have one very useful effect: -1000 limb damage to legs. This means that even DemonicSpiders like Deathclaws, Yao Guai, and melee-oriented Super Mutants can be crippled in one dart shot, effectively nullifying their speed advantage towards you and gives you ample time to switch to a more powerful weapon to finish them off. Combined with Sneak Attack Criticals and they won't know what hit them until it's too late, making it a [[LethalJokeItem Lethal Joke Weapon]]. This weapon was so much of a Breaker that it was excluded from ''New Vegas'' in an attempt to balance the gameplay, which did not sit well with some fans.

[[AC:Operation Anchorage, The Pitt, Mothership Zeta, Broken Steel Add-Ons]]
* The Tesla Cannon gained at the end of ''Broken Steel'' uses very common ammo and is (almost) a guaranteed 1-hit-kill, with area damage in case you miss.
* The Chinese Stealth Armor from ''Operation Anchorage'' makes you nigh invisible, provided you have decent Sneak (about 80). It allows you to sneak up to an enemy, from the front, set them on fire with a flaming sword, be pushed around by them, shoot them with little darts and plant explosives on them ''in full daylight'' without ever being detected. Thanks to the automatic critical when attacking undetected, most foes go down from the first hit. Got detected anyway? Retreat, wait a few seconds, be hidden again. Add to this that nobody gets alarmed by their friends suddenly going up in a blaze (more criticals), and you have the ultimate armor.
** On top of the Chinese Stealth Armor's greatness, you could put all the different variants of hats on while wearing the armor. Getting the DR of a light tank. '''And''' all of the stat bonuses (e.g. to Perception) from those hats stack too.
* Several of the unique items that comes from the MontyHaul that is ''Operation: Anchorage'':
** The Winterized T-51b Power Armor. Not the strongest armor in the game, but the developers accidentally put in the nigh-indestructible simulation version - odds are it'll never drop a single point of DR in an entire playthrough.
** The Gauss Rifle. Essentially an Energy Weapons sniper rifle, it has high damage, uses the common microfusion cells, and knocks down enemies on critical hits. Oh, and it has a critical multiplier of ''five''.
** It's also worth noting that a particularly sneaky player can place a corpse into the VR pod (in a seated position, which can be tricky to arrange), allowing them to place all their ''virtual equipment'' into the corpse's inventory ''before'' the game takes it away as you're waking up. The game will search your inventory for virtual items just a few seconds later and find nothing, allowing you to loot the corpse for all your ''invincible'' gear. Using this trick along with [[DifficultButAwesome shooting and stealing Jingwei's Shocksword out of his hand]] gets you an unbreakable set of armor (with some items you can't get any other way) ''and'' a shocksword which does electricity damage on hit.
* The steel ingot rewards from ''The Pitt'' are several powerful unique items, but some are worth special mention:
** The Steel Knuckles, having the ''lowest AP cost of any weapon in the game''. Combined with Paralyzing Palm, even Deathclaws are helpless in melee combat.
** The Perforator assault rifle beats out every other assault rifle in accuracy, comes with a scope to boot, and is silenced, allowing you to punch holes in enemies from a distance.
** The Auto Axe and its unique variant the Man Opener have rapidly spinning axe blades that are devastating against anything. The Trogs will run straight into the blades and be instantly sliced to death.
** The Metal Blaster, which simply put is a laser shotgun that fires a spread of nine beams. It's ineffective at long-range, but each of the nine beams can individually score a critical hit, so with some perks to increase critical chance it can one-shot a lot of enemies into ash.
* From a simple side-quest (or SequenceBreaking) in ''Point Lookout'', you can get the Backwater Rifle, a unique lever-action rifle. While Lincoln's Repeater barely beats it in terms of standard damage and clip capacity, the Backwater Rifle uses the very common 10mm ammo as opposed to .44 magnum and has a critical multiplier of ''five'' as opposed to two.
* Alien epoxy from ''Mothership Zeta''. It restores a ''fixed percentage'' of the durability on your equipped weapon based on your Repair skill - even weapons that can only be repaired by merchants. There are over a hundred throughout the Mothership and you can get an infinite amount after the expansion questline is completed.
* Even one of the basic alien weapons is a Game Breaker: the Alien Disintegrator. It packs a punch while having a clip size of ''100 shots'' and literally reloads with a mere press of a button. You'll have thousands of shots if you save up throughout the expansion.
* The Level 30 Perk "Almost Perfect," put in the game by Broken Steel. When you take it, it automatically raises all your SPECIAL stats to 9's. With careful planning, exploiting the Big Guns skill book glitch from the raider boss in Bethesda ruins, and abstaining from collecting any of the SPECIAL bobbleheads (with the exception of the Intelligence bobblehead in Rivet City) until after you take that perk, you can end up with a powerhouse of a character that has 10's in every SPECIAL stat, and 100 in every skill point. It takes a while to get there, but it's hilariously overpowered once you pull it off. Have fun!

[[folder:Fallout New Vegas]]
The game is chock-full of GameBreaker weapons and armor that can make quests and enemy encounters a breeze, even from the start of the game.

[[AC:Main game]]
* Shotgun Slug ammo. Normally, shotguns do a fair amount of damage divided into several small bullets (around 7). This means that, once you start facing armored opponents, your shots won't do diddly. However, slugs condense that damage into a single shot that only has one times the DT subtracted, only losing the 30% damage multiplier shot has afterward. Even better, with the perk Shotgun Surgeon, your shots ignore 10 DT, meaning that anything wearing light armor may as well be naked. The higher level shotguns, in particular, the hunting shotgun and its unique variant, Dinner Bell, can take out most any human target (excluding Lanius) with only a couple of shots at most. With Gun Runners Arsenal, you can buy Pulse Slugs, which do less damage, but are extremely damaging to robots and power armor. Combine this with Center Of Mass and Bloody Mess, and you can reduce enemies to a pile of bloody chunks that are no longer identifiable as human remains.
* Turbo, a rare chem which creates a "bullet-time" effect that slows down everything except for the player, allowing you to dodge any attack with minimal effort. It's not a game breaker by itself because the duration is normally very short, but with a certain combination of perks it is possible to get its duration up to a full 30 seconds (a full minute with one of the traits found on DLC)--more than enough for you to win any encounter with a single dose. The other balancing factor is that it is extremely rare, but this too can be overcome if you find the recipe, because the individual components are fairly common - the only "rare" ingredient is a Cazador poison gland.
* Debatably an InfinityPlusOneSword, PEW-PEW is easy to acquire fairly early in the game with a bit of knowledge and consuming every bottle of Sarsaparilla you come across. Sure, it eats ammo like a starving man devours fresh bread, and yeah it only can shoot two rounds before reloading. With this price however, comes an extremely easy to repair, improved holdout weapon, with insanely common ammo, that does some of the highest damage per shot, and with one of the highest crit multipliers and crit damages in the game. Even someone with no skill in energy weapons whatsoever can drop the highest level deathclaws in a few shots. Someone with a reasonably optimized energy weapons build, well... let's just say that those two cons pointed out above no longer matter.
* For those who don't mind outright [[GoodBadBugs glitches]], getting between 33K and 34K casino chip from any one casino and then dropping them causes the computer to... go funny in the head, causing the dropped chips to overflow and read as negative. Picking the chips up again adds them to your inventory...[[MoneyForNothing only they can't be removed.]] [[HilarityEnsues Even by cashing them in.]]
** Unless you save or load. [[PuffOfLogic Or look at them in your inventory, in some cases]].
* Another programming oversight allows you to map any kind of ammo usable for the gun you are currently wielding into a quickslot. [[AbnormalAmmo And then use it in another gun by switching to said weapon of choice and pressing the hotkey.]] This allows for truly broken combos like [[GatlingGood Gatling]] [[MoreDakka gun ammo]] being loaded into [[StuffBlowingUp an automatic grenade launcher]]. [[LethalJokeItem Or the Alien Blaster]]. [[NukeEm Or a Fat Man]]. [[RuleOfThree Or land mines]] to sell at enormous profit. [[OverlyLongGag Or the]] [[KillSat Euclid's]] [[NoKillLikeOverkill C-Finder]].
** This glitch has...interesting interactions with DLC ammo. Load 20 gauge 3/0 ammo into a weapon, and watch it fire four bullets at once. Particularly effective with sneak-attack criticals or a grenade launcher (as the explosion damage of each grenade isn't reduced at all). Or load one of the ''Gun Runners' Arsenal'' mini-nuke variants into the Laser Designator from ''Lonesome Road'' for a rapid-fire nuke-spamming pistol. [[UpToEleven That doesn't use up a single mini-nuke.]]
* The YCS-186 Gauss Rifle. Its accuracy makes it very easy to get headshots from such a distance sneak attacks can be easily made even with a very poor Sneak skill. It's ''already'' strong enough to kill most human enemies without a crit; long-distance sniping can one-hit kill against almost anything. You can find it for free pretty much as soon as you reach New Vegas, provided you know where to look. Just make sure whatever you shoot doesn't go flying somewhere you can't reach the body. For even more power, use Max Charge [=MFCs=], which will degrade the weapon more quickly but can be countered through use of weapon repair kits.
* Having Boone (enemy targets highlighted for you when you look down your sights) and ED-E (enemies show up on radar from the maximum distance possible) with you makes long-range sniping a breeze, especially if you have a suppressed sniper rifle like the Ratslayer.
** Boone ''by himself'' is a gamebreaker, as he can and will shoot every enemy you come across with pinpoint accuracy. Going anywhere with Boone will result in random rifle fire and [="+25 XP"=] notifications every few minutes. And that's ''before'' you find him an anti-materiel rifle...
* A surprising gamebreaker is the humble cattle prod. While it does pitiful damage against anything, it still stuns nearly every enemy in 2 or 3 hits, leaving them at your mercy if you repeatedly restore the stun effect. You could literally [[CherryTapping poke them to death]]. This includes Deathclaws, Giant Radscorpion Queens, Cazadores, or even Securitrons. If enemies get too close, this is basically the perfect emergency weapon.
** The Golden Gloves can do the same thing, but can also use unarmed moves and perks. These are also found in the casino floor of the Lucky 38, the same building that is most likely to be the player's house.
* Sneak attack criticals are absolutely devastating, especially combined with a headshot. That's why weapons like the Ratslayer, which has weak stats, can be gamebreakers. For reference just how low the Ratslayer's stats are, the Silenced .22 pistol, the absolute weakest pistol in the entire game, has slightly higher DPS than the Ratslayer. Only three pistols (.22 pistol, 9mm, and Maria, the unique version of the 9mm) do less damage per shot. Despite this, it becomes devastating when used with sneak attack criticals.
* The perk "Concentrated Fire" keeps increasing the hit chance of each attack if you target several times the same body part during a specific VATS sequence. Not only attacking with a fast weapon allows to be almost sure to hit, but the bonus is combined with the one gained from perks which reduce AP cost in VATS. Some tests ended with an anomalously high high accuracy at far range with weapons with which scoring such hits would logically be impossible (although the perk doesn't bypass the maximum 95% accuracy rate).
* The Missing Laser Pistol is an unremarkable, basic laser pistol that comes at a point in the game where it is laughably weak... and is ''also'' a quest item, meaning that no one and nothing in the entire game can remove it from your inventory. This means that you can walk it straight through casino security without having to put a single point in sneak, you can take it to the Fort, and you can take it with you into Dead Money which is a great asset seeing as all of your other weapons completely vanish.
* A fully modified laser rifle. It's versatile, has good aim, can zoom like a sniper rifle, excellent firepower and ammo is easy to come by. With this and sufficient Energy Weapon skills and feats, you can easily take down a Deathclaw on your own. You won't need another weapon again. The only downside is the ammo weight in Hardcore Mode, but that's a minor inconvenience by comparison.
* For the game-within-a-game, Caravan is trivially easy to win once you've built up enough even-numbered cards and face cards. By stacking the deck with 6, 8, 10, Jack, and King cards, you can not only get a solid 26 on every caravan within a few moves each, but can also easily sabotage your opponent.
* Jury Rigging lets you repair one weapon with any other weapon in the same of a few groups (i.e. one-handed guns, two-handed melee, etc.). Guns in the same group are often of wildly varying value--for instance, an anti-materiel rifle (5600 caps) can be repaired with a BB gun (36 caps) or Varmint rifle (75 caps). Since the repaired item will have a condition at least as good as the one it's repaired with, you can repair a very expensive item from any condition to full using one of a very cheap item that is in perfect condition (which are easy to find in poor condition and cheap to have repaired by [=NPCs=]). This effectively negates any effect condition will have one equipment you use, with a side-effect of ''destroying'' the game's economy: you can make thousands by just buying all of a merchant's high-tier but damaged items, repairing them, and selling them back for a massive profit. This doesn't have such a huge effect in the base game, because by the time you reach Jury Rigging's level requirement [[MoneyForNothing there's nothing money will really get you]], but ''Gun Runner's Arsenal'' adds loads of unique, powerful, and expensive weapons that you can only get from merchants--and they're often available extremely early in the game, just prohibitively expensive.
* Just having minor radiation sickness (which only has a -1 Endurance penalty) with the Rad Child perk gives you 2 [=HP/sec=] regeneration. This is more than ''every other regenerative effect in the game and [=DLCs=] combined'' (with the exception of one potentially-LostForever armor). If you're willing to handle the side-effects of the higher levels of radiation sickness, you'll be capable of standing perfectly still against anything short of a Deathclaw without dying.

[[AC:''Dead Money'' DLC]]
* The Automatic Rifle has good reload speed, good damage per shot, and good fire rate for high DPS. Its drawback is its high strength requirement and low accuracy. Its low accuracy doesn't matter at close range, which is what most fights in the DLC are, and enemies attacking in melee (like [[DemonicSpider Deathclaws]]) are ripped to shreds in seconds.
* The "And Stay Back!" perk gives every projectile from a shotgun a 10% chance of knocking them down. Since standard buckshot is 7 pellets, this gives meat shots about a 50% chance (14 pellets and about a 75% chance using the double-barreled Sawed-off shotgun or Big Boomer) of rendering any enemy [[ContractualBossImmunity but Ulysses, Gaius Magnus, or Colonel Royez]] helpless for several seconds. Since you can still knock them down when they're in the middle of getting up, forcing them to start over, you're pretty much guaranteed to [[CycleOfHurting stun lock]] any enemy that you can engage at close range.
* The lovely little gem known as the Holorifle. This is a scoped energy rifle that is, with Max Charge cells, outdone only by the Gauss rifles, but unlike Gauss rifles, a shot only requires one round of ammo, not four or five. Plus, it can be upgraded to do more damage, with reduced spread and improved condition. It also performs a damage over time effect to any enemy it hits. And while it can only be repaired by [=NPCs=] or weapon repair kits, at 100% condition, standard ammo causes no degradation. Use Overcharge or Max charge, though, and it takes damage. More importantly, it isn't affected by the Commando perk, or any of the energy weapons perks. While this sounds bad at first, this means that you DON'T need to take these perks if you're going to be a holorifle based character, freeing up several perks for character growth that you otherwise would not have available. The best part? You don't have to hunt for this weapon, you receive it at the start of Dead Money. The only thing you have to hunt for are the mods, two of which are located in areas you have to go to complete the storyline.
* Any player with a decent Luck stat can utterly break the game thanks to the Sierra Madre casino. After you've earned enough chips, one of the rewards will be chip vouchers which can be redeemed at a vending machine. Once you get back to the Mojave, three vouchers will be delivered to the safe in the waiting room every three days, for a total of 1100 chips. Using the vending machine in the room, you can convert these chips into anything on the menu, particularly Stimpaks and Weapon Repair kits. Congratulations, you now have infinite healing and weapon repair. To make it clearer, Stimpaks are 25 chips each, and Weapon Repair packs are 20. For those of you not wanting to do the math: 44 Stimpaks. 55 Repair Kits. For free. Every three days.
** A glitch in the X-Box 360 and PS3 version of the games gives the aforementioned complimentary vouchers awarded to the player at regular intervals a surprising use. When dropped the holotapes will float in the air, allowing a player who stocks up enough of them to build a chain of stairs to get to just about anywhere. It is popular to use mods to get the same effect in the PC.
** If that's not enough, while you're at the SM casino you can trade all the chips you have 1 to 1 for pre-war money (which has 0 weight and 10 base value). With winning the maximum amount at the casino (which can be pushed by winning a Slot or Roulette jackpot), collecting all the pre-war money and chips you can find (including the snowglobe) and bartering with the automated vendors, you can get over 15,000 pre-war money, which can effectively double your money gain without weighing you down any. If you want to push things even farther, you can take your time and scrounge up every last loose item from around the casino and suites (and after completion of the final mission, everything in the rest of the DLC area) and sell it to the holographic vendor in the casino's bar area, who has a huge stack of pre-war money in his inventory.
* The extremely heavy but valuable gold bars. Using numerous weight-reducing tricks, a player can, unencumbered, carry about 5-7 total, which is more like 1 or 2 if you're properly armed. They're supposed to represent letting go of greed (unlike Elijah, who will stop at nothing to get inside the vault). Though it takes some cleverness, it is possible to carry out the entire stash with time to spare by exploiting scripted events. Getting away with all the gold will net you 389,943 caps -- it's impossible to find enough vendors in the entire game (DLC's and all) who have that many collective caps, let alone enough to buy a single bar off the player. Though the weight-to-value ratio is extremely low, it's undeniably convenient.
** Where they truly break the game concerns vendors who are carrying the Gun Runner's Arsenal weapons, which can range from five to twenty thousand caps. Bring a few gold bars, and you can cut the price of, say, an Anti-Materiel Rifle with all of its weapon mods and a fair bit of ammo down to nothing.

[[AC:''Honest Hearts'' DLC]]
* The Compliance Regulator from ''Honest Hearts'' [[CherryTapping does an absolute pittance of damage]] but every time it lands a crit it will stun the target for several seconds, making them easy to pick off with a more powerful weapon. It also has an amazing fire rate so it's easy to spam hits at a distant target and land at least one crit before it reaches you and uses the very easy to find Standard Energy Cells for ammo. The best part is that ''nothing'' in the game is immune to the stun, not even any of the end game/DLC bosses which are normally immune to being knocked down. If you crit it, it will fall over stunned for quite some time.
* The Survivalist's rifle is a 12.7mm variant of the service rifle, or in other words, a semi-automatic rifle with hefty damage per shot. It's even more devastating when combined with...
* ...the Grunt perk, which boosts the damage of "infantry" weapons by 25%. This includes BoringButPractical weapons like the 9mm pistol and SMG (and their unique variants) as well as powerful unique weapons like the All-American, Thump-Thump, and the aforementioned Survivalist's rifle.
** The [=JSawyer=] mod removes the All-American (and its non-unique variant, the Marksman Carbine) from the list of weapons affected by Grunt. Some of the weapons ''added'' to the Grunt list are ''grenade launchers'', as well as the very powerful This Machine, but this got removed. It's the only instance of a weapon getting removed from a perk list, too. That's pretty telling of how good this combination is.
* One of the new craftable items added by ''Honest Hearts'' is the Healing Poultice. It uses ingredients that are extremely common in Zion (and al but one of them are common in the Mojave as well), restores a hefty amount of HP, weighs very little, and restores limb HP as well. You'll never need another healing item again.

[[AC:''Old World Blues'' DLC]]
* The Tarantula frequency sonic emitter from Old World Bues is a pretty decent weapon on all its own, does good base damage, uses common ammo, sets enemies on fire with a critical hit. However, due to a game glitch, sometimes when scoring a crit the critical kill animation will play even though the target is still very much alive. Since the critical kill animation consists of exploding the enemy's limbs off, this results in a chance for an instant kill.
* The perk "Them's Good Eatin'". 50% chance of finding some [[HyperactiveMetabolism rather filling foods]] every time you kill something, foods which can be crafted into something with even more powerful healing. You quickly start drowning in healing food, which you can use to recover HP at absurd rates, or simply sell, as they're also very, very cost-effective.
* Christine's COS Sniper rifle is a silenced sniper rifle with higher base damage than the regular sniper. At medium range or longer, it kills everything, and is a perfect weapon for stealth kills at any range. Its only drawback is that, as a sniper rifle with low ammo capacity, it's worthless at close range. That's why you pair it with the Automatic Rifle above, as they use the same ammunition.
* Turbo's GameBreaker potential is limited by its aforementioned rareness. The Implant GRX perk can be taken at level 30 and has the exact same effect as a dose of Turbo, albeit with a shorter duration. However, with the previously mentioned drug extending perks a single shot of GRX lasts 20-30 seconds, depending if you have rank one or two of the perk, more than enough to kill anything in the game, and if somehow you can't finish a fight up in time, feel free to take another FOUR to NINE doses (rank 1 or 2 respectively). That reset daily. Oh, and did I mention it's impossible to become addicted to it. It stays with you in Dead Money. The only real downside to basically being the Flash with a gun is an 8 endurance entry fee.

[[AC:''Lonesome Road'' DLC]]
* [[spoiler:ED-E]] is a deliberate GameBreaker given to you right at the start of the mission. Most notably, after collecting two circuit boards (one found in the same complex where [[spoiler:ED-E]] was activated), you will receive the option to have your weapon repaired by 25% ''once a day'' (thereby saving you thousands upon thousands of caps in repair fees), and you'll get free ammo every day (which, depending on your Speech or Repair skill, will net you [[=Energy/Microfusion=]] cells, flamer fuel or satchel charges). You'll never have to worry about weapon degradation or running out of ammo for the duration of the DLC. The best part, however, is that all these benefits ''[[spoiler:transfer over to the main game's ED-E]]'' - have fun!
** Not only that, but just ''installing the DLC'' makes main game ED-E a traveling Workshop and Reloading Bench.
* The best rocket launcher in the game, Red Glare, is more or less handed to you a third of the way through your quest, and three mods for it are sold at every Commissary in the Divide. If you've been saving your caps (or if you decide to abuse the Commissary's replenishing stash of caps), you can get all three mods as soon as you get it, and use the fully-upgraded auto launcher with the best zoom of any explosive weapon (4.35x) in the game immediately.
** On that note, you'll be finding hundreds (literally) of rockets for the weapon throughout the DLC. With a Science skill of 65 and some of the odds and ends you'll be finding dozens of throughout the map or can buy for dirt cheap, you can use ED-E to convert the regular rocket ammo to [[StuffBlowingUp high explosive]] or [[KillItWithFire incendiary]] variants. The best part? The base value of a rocket is 25 caps. The variants go for ''six times that''.
* The "Voracious Reader" perk, which allows the player to craft skill magazines from the [[VendorTrash damaged books]] that you can find anywhere (if you already own at least one magazine of the concerned skill). This adds up greatly over the long run, as virtually any building you visit will have ruined books and magazines.

[[AC:''Courier's Stash'' and ''Gun Runner's Arsenal'' DLC]]
* The Vault 13 Canteen is a small item which you gain at the beginning of the game if you own the ''Classic Pack'' preordering bonus or the full ''Courier's Stash'' DLC. It is an infinite use canteen which is automatically drunk by the Courier. In casual mode, it only heals a small amount of hit points. In Hardcore mode, it decreases the thirst meter like any other water bottle; it isn't enough to completely remove the need to collect and drink water, but it helps a lot.
** The healing from the canteen is hardcoded. If you play with the ''Project Nevada'' mod, its default settings turn off the healing factor of food and water, but this doesn't affect the canteen.
* The Esther unique Fat Man in the Gun Runners Arsenal. Not only does it do the most damage per shot of any weapon in the game, but it adds radiation and armor resistance to the wielder. While it weighs forty pounds and uses the heaviest ammo, this former can be halved and the latter can be alleviated by letting your companions carry some ammo. What makes it such a game breaker is that the DLC also adds a bunch of mini-nuke variants that can be purchased in respectable quantities every three in game days for a laughably low price. These give the weapon surprising versatility for such a powerful weapon. For example the tiny tots nuke splits into smaller nukes, allowing you to carpet bomb areas or use the weapon like an atomic shot gun, since each explosion's damage will be reduced by your armor and the weapons damage threshold. While its still not something you use all the time, it will still likely fell most of the opponents you find even slightly difficult otherwise.

[[folder:Fallout 4]]
* By returning to Vault 111 with Dogmeat, you can use a {{Good Bad Bug|s}} that allows him to unlock the Master locked container early and get the Cryolator and some ammo. While you won't have much ammo for it until much later (making the weapon somewhat TooAwesomeToUse), it's a very powerful DiscOneNuke, especially for Legendary enemies, bosses, and difficult encounters. A lot of players are suspecting that this exploit will be patched in the future, but it is still doable as long as you have a disc copy of the game and delete the downloaded patches and then start a new game.
** If you don't wish to use the GoodBadBug but still don't wish to level up your lockpicking perks, Cait can unlock it for you, all you need to do is to find her.
* Dogmeat has another {{Good Bad Bug|s}} that allows you to duplicate items, including the "You're SPECIAL!" book that gives a free point in one of your SPECIAL attributes (Which requires 42 perk points or 42 SPECIAL books).
** More ridiculous still: This can dupe '''any''' item. Need caps? There's a set of three gold bars in the root cellar of one of the houses in Sanctuary. They're 200 caps each, easy. Need adhesive? It can dupe Duct Tape, Wonder Glue, you name it. Not enough? Even '''Fusion Cores''', '''Mini Nukes,''' and '''Legendaries''' can be duplicated. With enough patience, you can get a plentiful supply of any material you need, or any weapon or item.
* [=MacCready's=] companion perk "Killshot". Normally it gives a 20% extra chance to headshots in V.A.T.S., but due to a (currently patched) {{Good Bad Bug|s}} it maxes chances to hit an enemy's head in V.A.T.S. to 95%. With that, you can score headshots as long as your enemy's head is revealed in the slightest, even if they are mostly concealed behind cover or foliage, regardless of range.
* You can get Righteous Authority by completing the first Brotherhood of Steel mission. It's a DiscOneNuke that uses very common and cheap ammo, is effective against nearly everything (including the newly-buffed robot enemies), stays useful throughout the game, does double damage on a critical hit, refills your critical meter 15% faster, and has a scope to boot.
* The Syringer seems like a meh weapon at first, until you get your hands on some of its different ammo types: they allow you to cut an enemy's damage resist, poison them, or instantly blind them. These effects make it incredibly useful, particularly against larger enemies like Deathclaws.
* While it's at the bottom of the perk tree, the Ricochet perk has a chance to cause an enemy's ranged attack to rebound and instantly kill them. Most enemies have ranged attacks in this game. Do the math. And just to make it even better, a {{Good Bad Bug|s}} also made the effect apply to some ''melee'' attacks too.
* A tricky but particularly ridiculous glitch allows your to get infinite caps, levels, and items by buying one type of ammo from a vendor and very quickly selling one before selling the rest. This glitches out the one bullet, allowing you to keep selling it over and over again while gaining caps and XP to boot.
* If you take it early and keep your Intelligence low, the Idiot Savant perk can give you so much XP that you can go up multiple levels just from completing quests. Even if your Intelligence is ''very high'' the boost comes often enough to be tremendously useful, which will further be boosted by Int like regular XP--a character with 10 Int and maxed Idiot Savant will average slightly more XP than one with 1 Int. The only downside from it is that you ''will'' get annoyed at the [[MostAnnoyingSound constant HYUK HYUK sound it makes when it activates]].
** Although 10 Intelligence will only have a 2.5% activation rate for Idiot Savant, players can still use SaveScumming by quick saving before turning in quests that are worth a lot of XP and then reloading over and over again until Idiot Savant activates.
* A Luck build can become ''very'' powerful. Being able to force {{Critical Hit}}s to happen as long as you have a bar is really nice, especially against bosses and Legendaries. With Critical Banker, one can store up to four of them at max level (with an added chance of gaining an extra crit when your bar fills up). Now combine that with Better Criticals and certain weapon mods to increase crit damage, Grim Reaper's Sprint (at max level, it triggers 1/3 of the time to recover all AP ''plus'' increase your critical bar) and Four Leaf Clover (each hit in V.A.T.S. has a random chance to instantly fill a crit bar, chance increases as level goes up) and you'll be pulling so many deadly critical hits out so fast it's not funny. In particular, the Double-Barrel Shotgun can get two simultaneous crit-boosting mods, which with other sources can let a crit add 725% the weapon's base damage when [[AlwaysAccurateAttack every single pellet will hit the target]].
* The "Kneecapper" ability on legendary weapons (20% chance to cripple both legs per hit), when found on any weapon that can rapid fire, is pretty much this game's version of the Dart Gun from ''Fallout 3''. Just pump a few bullets in an enemy and even legendary deathclaws will be at your mercy. The only downside is that it relies on a lucky find after killing a legendary enemy.
* Legendary weapons and armor are intended to be buffs over normal weapons but can easily become this if they have the right effect. For example some weapons can deal double damage if the enemy is at full health, which stacks with the sneak bonus. A .50 cal sniper rifle can one shot almost any enemy this way.
* The Gauss Rifle hits extremely hard in this game, ''much'' harder than the .50 cal sniper rifle. While it's incredibly rare (though you can buy the unique variant) and you won't be finding legendary versions, it does so much raw damage that you won't need special bonuses. And its unique variant, The Last Minute (obtainable after helping the Minutemen reclaim their base of operations and assisting them in a couple more sidequests), is even more ridiculously powerful.
** That's not even the ludicrous part. The REAL craziness starts when you put, of all things, a ''suppressor'' on it. You see, there are two Agility-based perks, Mr. Sandman and Ninja, that increase sneak attack damage. Ninja increases the base bonus multiplier (from x2.0 to x2.5 and so on) while Mr. Sandman increases it percentage wise (+50% at the highest rank) but ONLY for suppressed weapons. With a suppressor on your Gauss Rifle, those perks, and a Stealth Boy, a fully charged shot can outright kill ANYTHING just short of Liberty Prime himself.
** There ARE legendary Gauss Rifle drops, rare though they may be. And they're just as devastating and you'd expect.
* With enough Caps, one can buy the Overseer's Guardian from Alexis Combes at Vault 81. It's a Combat Rifle (the third-tier rifle) that fires ''two'' shots at a go for the price of one bullet, essentially doubling the damage you deal out, has a very high ammo clip, and unlike the aforementioned .50 cal Sniper or Gauss Rifle, it has a ''much'' better rate of fire. Combine this with a sniper build and watch the enemies die from afar.
* The Alien Blaster isn't quite an InfinityPlusOneSword anymore that can melt enemies in a single shot, but you can make it practical. With a high Science skill it can be converted to use standard micro-fusion cells. This reduces the damage and clip size.. by about 2% each. It still does fabulous damage with cheap as hell ammo.
** Perhaps more impressively, it has an incredibly low AP cost for each shot, for a weapon that deals this level of damage. At 10 Agility, it can fire between 5-7 shots, at 50 damage each. With a maxed Gunslinger perk, that transforms to 100 damage per shot. For a VATS-Based build, that's obscene, especially once you start getting critical hits involved.
* Due to the game's more fast-paced "realistic" gunplay, an Explosives build can be unbelievably powerful in this game, [[MagikarpPower although it takes a while for it to truly shine]]. However, with max Demolitions Expert and a modded rocket launcher or a Fat Man, you will basically obliterate everything in the game with little trouble.
** Legendary firearms with the Explosive effect are major powerhouses on their own. The effect of dealing a bit of explosive damage, which isn't as heavily effected by armour, to a small area makes it great for clearing crowds. However, there is an additional bonus to this effect: ''it's not effected by range''. You can take a weapon that's normally not good at range with this effect, like a machine gun (like Cricket's "Spray 'n Play) or even better '''''[[ShotgunsAreJustBetter a shotgun]]''''', spray away, and watch the pretty little explosions. Combine this with an aforementioned Explosives build and the game might as well just end right there.
* If you do enough of the Railroad cache sidequests, you can talk to Tinker Tom and unlock the Ballistic Weave mod, which allows you to add armor to most forms of basic clothing, including clothing that can be worn under a full set of armor. The ingredients are rare, but so very worth it. Just how broken is this? The Mk 5 version provides a whopping 110 to ballistic and energy defense, which rivals most sturdy armor in terms of effectiveness. It also works on a select few ''hats'', meaning you can mod a '''fedora''' to give better head defense than freaking ''power armor''. This gives you a total of 220 ballistic and energy defense along with Luck/Charisma bonuses from both the hat and glasses, which helmets do not allow to be worn together. Combine with modded Heavy armor and you easily pass 300 ballistic and energy defense. Add the ballistic and energy defense perks and that can potentially pass 400.
** Even better, the materials might be rare, but Tinker Tom still starts selling enough Ballistic fiber clothing at a decent enough price that you can very easily scavenge enough Ballistic Fiber to upgrade whatever you want to the highest level possible of Ballistic Weave.
* While finding one is a purely luck-based endeavor, any legendary can become incredible if it has the Double Shot attribute (like the above-mentioned Overseer's Guardian) - Two shots for one ammunition, which essentially equates to double damage for most weapons. Of particular note is a Plasma Rifle with such a modification. Even on Very Hard, little can stand before you with one.
** Speaking of Plasma Rifles, a modded Plasma Rifle - or even just a modded out pistol - is absurdly powerful, especially combined with the proper perks. A plasma sniper rifle when modded does more than 100 damage total before perks are added. Perks will double the damage, give this weapon the ability to penetrate armor, and have a bonus to making headshots. It is balanced by a high AP cost, but the right build can handle that. If you can manage a build that has the critical bar and the AP bar fill one another, you can become a murder machine.
** One of the purchasable weapons with Two-Shot is the Big Boy from Diamond City's Arturo, a ''Fat Man'' with Two-Shot. Since it's possible to perform the "infinite caps from ammo" glitch on him, it becomes really easy to obtain the Big Boy. Now add the "MIRV Launcher" mod to it, and you get to fire out two clusters of six nukes, giving you ''twelve'' mini nukes for the price of one!
* A wounding legendary on any fast weapon completely trivializes anything, doing an absurd 25 bleed damage per hit. Bleed damage effects everything (even ''robots''), completely ignores damage reduction, and stacks damage (two hits means they are taking 50 damage even if you somehow hit twice instantly). This becomes even more hilarious when said weapon has a base customization that - you guessed it - adds more bleed damage.
** For a great example, one needs look no further than Pickman's Blade, which is easily obtainable through a short low level sidequest. It not only has wounding, but it's also a combat knife already upgraded to it's highest rank. What does this mean? Every single hit from this little beauty does 40 extra unmitagatable damage. And being a combat knife it has the fastest melee swing in the game, able to swing 3 or 4 times for every swing of a slow speed weapon.
** If you manage to find a wounding Ripper, the game may as well just roll credits. The ripper attacks over 5 times per second, with ''each hit applying the aforementioned bleeding effect''.
* The blade that you get at the bottom of Dunwich Borers is special, because it ISN'T legendary, but rather just a weapon with a unique mod. The mod boosts base damage and does wounding damage, and can be detached... and added to a legendary machete that also has a wounding effect. So you can do even more wounding damage.
* The Shishkebab can also be obtained easily by killing the boss in Saugus Ironworks, while also completing the nearby settlement's quest which also gives you control of the said settlement.
* As Mini Nukes and Fat Mans are much more common in this game than ''Fallout 3'', the Fat Man actually becomes more viable in open spaces. The "MIRV Launcher" mod however makes this ridiculous. You launch a projectile that splits into six Mini Nukes. What makes this broken compared to ''Fallout 3's'' MIRV? [[AwesomeButImpractical Fallout 3's MIRV required you to use eight mini nukes to fire it]]. ''4'''s requires ''one''. Yes, ''six Mini Nukes for the price of one''. The Big Boy takes this even further- since it comes with the Two-Shot attribute, you get ''twelve'' Mini Nukes for the price of one.
* If a settlement produces more water than the population consumes, the excess water will be periodically deposited in the Workshop in fairly large quantities. 100% free healing that heals roughly as much as stimpacks for much of the game (without relevant perks to upgrade Stimpacks). On top of that, when you use a stimpack you're treated to a short animation of the Sole Survivor injecting themself with a syringe, during which time you can't run or shoot or anything, even during combat. Purified Water doesn't have this problem, so unless you're healing limb damage, Purified Water is a lifesaver well throughout the game.
* The skills that let you control other creatures (Animal Friend, Robotics Expert, etc) let you control any NPC that fits in that category. Deathclaws count as animals. Sentrybots and Assaultrons are robots. Brotherhood Of Steel members in full power armor are still humans. Even if all you have is one level difference, with the perks high enough, you can control them... and sick them on enemies that may be the same, or even a higher level, but are no match for them. You may have to manually control them to order them to enter buidlings, and can't fast travel with them, but they're still incredibly powerful allies to have.
* Chems have become massively overpowered in this game thanks to chemistry crafting stations and certain perks. The most noticeable change is with Jet, one of the more common chems. In previous games all it did was boost your AP for a short time. Good, but not great compared to the rarer stuff. Fallout 4 tweaks it so that it now behaves like [[BulletTime Turbo]] (a GameBreaker itself from New Vegas mentioned above) without the rarity to restrict it. Even better, players can now mix it with other potent chems like Psycho and Buffout for a truly devastating cocktail. Still not good enough? Take the second rank of the Chem Resistant perk and you won't even have to worry about addiction, which turns these dangerous drugs into magic potions with no real drawbacks. Aside from a few rare situations (like when an enemy has a Fatman or hostages) a handful of these boosted chems and a gun with a lot of ammo/a large stash of grenades are all you'll need to clear the room.
** Jet and Jet Fuel are not just useful chems for combat, but they also are the easiest chems to manufacture (Jet requires only plastic and fertilizer, and Jet Fuel requires Jet and Flamethrower fuel). Jet Fuel, even at level 50 and above, gives 13 exp per unit, and Jet gives 1 exp a unit at that level. 14 exp total, even at a level where most basic enemies give that amount. So, provided you can find a plentiful supply of both, you can power level hard for as long as you have the materials, and end up with a powerful and useful chem. Plus, even without using these chems, they can be useful in that the components to manufacture them are usually less expensive than the sale price, especially if you just scavenge the materials necessary. Flamer fuel is common at Saugus Ironworks, provided you're willing and able to tangle with the Forged, and plastic items are common throughout the Commonwealth. Fertilizer is slightly less so, but still obtainable.