History GameplayDerailment / MassEffect

** There was a bug in the Xbox 360 release of the game that allowed the player to max out his/her companions' skills at level 6, provided they pressed the right button at the point they unlocked the final tier of a skill upgrade. It utterly broke the difficulty in the game and was quickly patched out, but enjoyed a brief bout of popularity at launch.

** If you have the ''Leviathan'' or ''Citadel'' [=DLCs=], you can sabotage the genophage and keep Wrex alive, provide that you never go back to the default docking bay. Doing so ensures that you have full Krogan and Salarian support, and Wrex still treats amicably when he sees you on Earth in the ending.

** As mentioned on the GoodBadBug page, it's possible to use a simple glitch (talk to a certain NPC on Noveria) to max out your Paragon and Renegade scores very early on, utterly breaking the morality system in the game. However, many players who use this glitch enjoy it because it gives them a greater degree of flexibility in terms of conversation options.

** A key part of many speedruns is the ability to exploit collision detection via SaveScumming, which would often allow the player to skip vast sections of the game and allow them to get to places that are normally inaccessible. A key part of a [[https://www.youtube.com/watch?v=AaHO5Wn0PDM Games Done Quick 2013 speedrun]] had the player use this method to skip large chunks of the story, including the Benezia fight and most of the ending. As such, most speedruns of the game can be done in three hours or less in the hands of a skilled player, and no tool-assists are necessary.
** The Mako was an absolutely broken gameplay mechanic, as players quickly realized that it could be used in unintended ways. Chief among them was the ability to get the vehicle into places that were normally blocked off from vehicle access (either by using alternate routes or exploiting parts of the level geometry), and using it to whittle tough enemies down to almost no health then exit the vehicle and get the killshot for massive amounts of experience. As an unintended side effect, this caused many cutscenes to become bugged-out and glitchy, resulting in characters flying past the camera at breakneck speed during conversations or not being present at all.
** The Therum "mining-laser" glitch is an exploit that was located in a place you couldn't possibly miss going to (breaking Liara out of confinement), was absurdly easy to do (wait for an XP notification to pop up, save and reload, then repeat as many times as necessary) and allowed the player to max out their level long before the endgame. Even the official Mass Effect Wiki references this in the opening paragraph about gaining experience on its associated page.

** There was a bug in the Xbox 360 release of the game that allowed the player to max out his/her companions' skils at level 6, provided they pressed the right button at the point they unlocked the final tier of a skill upgrade. It utterly broke the difficulty in the game and was quickly patched out, but enjoyed a brief bout of popularity at launch.
** The ''Aegis Pack'' DLC had a gun (the Incisor) that was bugged and made your companions incredibly overpowered on Insanity difficulty. Normally, squadmate weapon damage is reduced on higher difficulties - ''except'' for weapons added via DLC, making this gun the king of the hill.
** Like the first game, it was possible to exploit enemy behavior and get the drop on large groups by staying just outside their detection range and picking them off via sniper rifles. Doing so marginalizes some of the tougher enemy battles in the game, including the fight against the Scions on Horizon.

** The "N7 Special Ops" War Asset can be this if you play enough multiplayer. When any one of the 6 classes gets to level 20, you have the option of promoting the class, resetting it's level to 1 adding 75 points to the war asset. This can be done over and over without restriction, eventually amassing so many war assets it no longer becomes possible to get any of the Low EMS endings, even if you have only 50% galactic readiness and lack the "Extended Cut DLC" meant to lower the War Asset requirement to get the best endings. This single War Asset will make ever other War Asset worthless fodder. Of course, you have to do this a lot - as in, spend more time playing multiplayer than any two playthroughs of the regular singleplayer campaign.
** The sheer number of broken and overpowered weapons, power combos and abilities (so much so that it dominates [[GameBreaker/MassEffect the associated Game Breaker page]]) means that it's not a question if you find something that trivializes the highest difficulties, but ''when''. One DLC gun similar to ''2'''s Incisor rifle (the N7 Typhoon) made Insanity difficulty an absolute joke due to it not coding damage output for squadmates properly. Hand it to Garrus and spec his abilities to focus on maximizing weapon damage, and watch him [[https://www.youtube.com/watch?v=ZPbB4qfsA14 walk you through most of the game.]]

** The ''Aegis Pack'' DLC had a gun (the Incisor) that was bugged and made your companions incredibly overpowered on Insanity difficulty. Normally, squadmate weapon damage is reduced on higher difficulties ''except'' for weapons added via DLC, making this gun the king of the hill.

** The sheer number of broken and overpowered weapons, power combos and abilities (so much so that it dominates [[GameBreaker/MassEffect the associated Game Breaker page]]) means that it's not a question if you find something that trivializes the highest difficulties, but ''when''. One DLC gun similar to ''2'''s Incisor rifle (the N7 Typhoon) made Insanity difficulty an absolute joke due to it not coding damage output for squadmates properly. Hand it to Garrus and spec his abilities to focus on maximizing weapon damage, and watch him walk you through most of the game.