Games that are particularly popular to speedrun such as Super Metroid or Metroid Prime typically have opportunities for "sequence breaking" which involves getting certian items early in order to progress through sections of the game earlier than the player should be able to. An example in Metroid Prime involves a bug that allows a player to increase their jump height, allowing a skilled player to obtain the most powerful weapon in the game, the Plasma Beam, less than a quarter of the way into the game.However, sometimes these time-saving sections seem to be anticipated by the programmers. If you get the Plasma Beam in Metroid Prime early then you'll be ambushed by a Plasma Trooper enemy, a fairly strong type of enemy who can only be hurt by the Plasma Beam. Obtaining the Plasma Beam later in the game does not cause a Plasma Trooper to appear.
Another example from the Metroid series is in Metroid Fusion, which is an incredibly linear game by Metroid standards. In Fusion, a clever use of the Shinespark maneuver will allow a player to bypass an upgrade necessary for escaping the area that the player is otherwise trapped in. If the player manages to pull this off, the game's mission control will acknowledge that you broke the sequence of an otherwise linear game with a special message. While it's cool that developers seem to be aware of what players like to do with their games, the glitch allowing for the player to obtain the Plasma Beam early was curiously removed in the Metroid Prime Trilogy collection.
Glitches, bugs, errors, or whatever else they are called are examples of programming oversights on the part of the game's programmers. Sometimes, these glitches can be harmless graphical errors that don't really effect the gameplay. Other times, you can get potentially game-breaking bugs like the "Handcuffs" glitch from Street Fighter II, or any of a dozen of shoddily programmed sections of Donkey Kong 64.
In the current age of gaming, glitches can and often are fixed through swift patches. Maybe I'll touch on this in a future post on day one DLC... However, not all game companies are so swift to condemn glitches; Guilty Gear had a glitch termed "Jump Install" that allowed players to jump without actually jumping, which in turn "stored" the jump to be used later in a situation where a character wouldn't normally be able to jump. Interestingly, this was never fixed in future versions of the game, despite re-released versions of the game - like Guilty Gear XX: Reload - fixing other issues with the game. As Guilty Gear was a game made to be played competitively, Jump Installing still remains usable as part of Guilty Gear's metagame. Additionally, another ArcSys game Persona 4: Arena had a glitch where the character Yosuke was able to descend while airdashing, allowing for a more aggressive playstyle. Despite numerous game-breaking glitches being fixed in patched after Persona 4: Arena's release, Yosuke's "gliding" bug was never fixed, and as a result has been adapted into the metagame much like Guilty Gear's Jump Install.
A less serious examples in Valve's FPS game Team Fortress 2 involve a glitch where when the game goes into overtime, the Announcer's voice files will glitch, causing her to yell "overtime!" over and over again. While this bug was fixed, it proved so popular that Valve gave servers the option to have the Announcer to continuously say "overtime" or not. In the original Pokemon games (Red and Blue versions) a highly desirable glitch that allowed the player to clone multiple items sometimes manifested an extra monster known as "Missingno" that fans have humorously interpreted as a sort of reality-warping Lovecraftian horror due to the numerous amount of game-breaking glithes that occur after encountering the inexplicable monster.
It's even got an single unnerving eye that it just watches you with. |
Image Source
www.wikipedia.org
Further Reading
Wikipedia article on Missingno
Demonstration of Guile's "Handcuffs" glitch
Demonstration of Yosuke's "Gliding" glitch