Pokémon Yellow
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Pokémon Yellow is the "third game" of Generation I released worldwide, i.e. the upper version of Pokémon Red and Blue. It uses the same game engine as its corresponding version in Japan, which is also usually known as "Japanese Pokémon Yellow" in English. However, this version is not named after a color in Japanese, but rather as "Pocket Monster Pikachu" (Japanese: ポケットモンスター ピカチュウ). In Japan, it is the fourth version in Generation I, the paired versions being Japanese Pokémon Red and Green and the third version being Japanese Pokémon Blue.
Compared to Pokémon Red and Blue, the game engine of Pokémon Yellow is slightly updated to support various special features of the starter Pikachu (most notably, following the player on the overworld), and for Western releases also to support color palette changes on the Game Boy Color. Several glitches are fixed, but the game remains easily breakable, mostly thanks to the trainer escape glitch and the save corruption glitch. A new major glitch introduced by Pokémon Yellow is the Pikachu off-screen glitch, which can be used to achieve arbitrary code execution (ACE), but this is generally less convenient than starting from the trainer escape glitch and doing arbitrary code execution with a glitch item, like in Pokémon Red and Blue.
Glitch Pokémon, glitch items, etc. can be accessed in Pokémon Yellow just like in Pokémon Red and Blue, but due to various changes in the game shifting bytes around, their behaviors are often different from their Red and Blue counterparts.
Game-breaking glitches
Despite the developers' attempt to fix glitches, some of the most powerful game-breaking glitches in Red and Blue remain in Pokémon Yellow. Save corruption remains the fastest way to break the game, with the same downsides of relying on a very precise timing (for hard resetting) and being hard to exploit cleanly.
The earliest point a trainer escape could be performed is still in front of the last trainer in Viridian Forest, and again this early in the game it is impossible to encounter a MissingNo. (or any other glitch Pokémon) with the Special stat encounter to break the game. The speedrun method for Red and Blue relies on very fine details of the game engine, and will not work on Yellow. Instead, speedrun routes of Yellow usually exploits the text box ID matching aspect of the trainer escape glitch, displaying a glitch text box that reads its contents from the OAM buffer, which can be manipulated to have a 0xFE byte as the first byte of the glitch text box, which becomes a glitch mart. Various glitch items, including the ACE glitch item 4F, can be purchased from this glitch mart. To access this glitched mart in RTA, runners would perform a carefully designed sequence of actions consisting of both luck manipulation and glitch setup, collectively known as "THE Manip"[1]. One advantage of "THE Manip" is that, since it does not execute arbitrary code from the RAM per se, it can also be used in speedrun categories that do not allow ACE (where glitch items can be bought to enable non-ACE glitches like the Rival's effect or the LOL glitch).
For casual players, the most common gateway to breaking the game is still MissingNo., encountered by using the trainer escape glitch later in the game.