"Game glitches" refers to unexpected issues or errors in video games that cause unintended behavior, such as characters getting stuck, objects disappearing, or the game freezing. Full definition
But there are people who use in game glitches to gain an advantage, even on dedicated servers. (n4g.com)
Put simply, a lot of people have started to treat video game glitches like they're a bad thing, and decided that their existence in a game is somehow proof the developer got lazy. (gamingreinvented.com)
overkill is completly different gun game, great game but took it back due to the gun acting up on the wii and glitching up in certain parts of the game (arcadeheroes.com)