Glitching is an activity in which a person finds and exploits flaws or glitches in video games to achieve something that was not intended by the game designers. Gamers who engage in this practice are known as glitchers. Glitches can help or disable the player.
"Glitching" is also used to describe the state of a video game undergoing a glitch. The frequency in which a game undergoes glitching is often used by reviewers when examining the overall gameplay,[1] or specific game aspects such as graphics.[2] Some games such as Metroid have lower review scores today because in retrospect, the game may be very prone to glitches and be below what would be acceptable today.
Video game glitches that go to "out of bounds" areas are mostly performed by either moving through walls or corners or jumping to places in the map that do not have invisible walls. For example, in Tony Hawk's Underground 2, in the Los Angeles level there is a glitch that can allow players to leave the proper play area and enter the background.
In "out of bounds" areas, many maps have hollow objects that the player can move through freely. These objects usually are in the distance and are for decoration. The floor or terrain can also be hollow. The floor can appear the same as a normal floor but moving over it will cause the player to fall as if it does not exist. Depending on the game, after falling a certain distance the player will freeze, die, respawn on the map again or just keep falling. A good example is in the Nintendo 64 game The Legend of Zelda: Ocarina of Time there is a section of "wall" at the entrance to the water temple that will allow players to fall through the ground. Eventually players respawn rather than the game crashing.
Many other glitches may also include background music being played at the time it was not intended to play, such as the Western Super Mario Bros. 2 (based upon the Japanese-only game Doki Doki Panic) has a major glitch where the Subspace music (the Overworld background music from original Super Mario Bros.) can be played outside of Subspace after the player becomes invincible and enters Subspace and leaves before invincibility drains away (this glitch was fixed up for Super Mario All-Stars and Super Mario Advance so that Subspace music can only be played in Subspace). One of the best known examples for glitching in an online game is on Grand Theft Auto: IV where people can glitch into rooms they're not supposed to, or get under the map (for example by glitching a helicopter to spawn under the map and fly into beta rooms).