games, players start their journey across Kanto from their hometown, Pallet Town, eventually defeating the eight Gym Leaders and the Elite Four. Unlike other games, the player starts off with a Pikachu and the rival with an Eevee.
Team Rocket battles feature yet another special, anime-based surprise, as Jessie and James show up, along with their Pokémon, Ekans, Koffing, and Meowth. Beyond these changes, the plot of Yellow is very similar to that of the Japanese Red and Green and Japanese Blue as well as of the Western Red and Blue.
- Pikachu is the only starter Pokémon the player can choose and travels with the player on-screen, outside of a Poké Ball like Ash's Pikachu. It will also cry like Ash's Pikachu in the anime, with its cries now voiced by Ikue Ohtani.
- This Pikachu cannot be evolved or released.
- The rival starts with Eevee.
He will eventually have a different team based around one of Eevee's evolutions depending on how the player fares in the first two battles with the rival (the second being optional), at Professor Oak's Laboratory and Route 22.
- If the player wins both, Eevee evolves into Jolteon.
- If the player wins one battle and loses or skips the other, Eevee evolves into Flareon.
- If the player loses or skips both, Eevee evolves into Vaporeon.
- A minimal friendship system is implemented to track how Pikachu feels about the player.
- Gym Leaders have different teams, some based on those that appear in the anime.
- Level-up learnsets and TM compatibility are altered slightly for certain Pokémon. Charizard, for example, can now learn Fly via HM02.
- Support is added for the Game Boy Printer.
- If the player does not have 500, they can still enter the Safari Zone.
The player will have to pay any money they do have and will receive a number of Safari Balls proportional to the amount paid (but at least one).
- Kinesis is given to Kadabra as its signature move. In the previous games, Kinesis was never used and the only way it might appear would be if randomly called by Metronome.
- A new mode, "Colosseum 2", was added to the Cable Club.
- The Viridian City Poké Mart now sells Potions. The NPC complaining about Potions not being sold in Pokémon Red and Blue now states that the Mart finally sells Potions again.
- The chain of events leading to the player obtaining the starter is slightly different:
- The player now takes one step further into the tall grass before Professor Oak
comes along. Now himself standing in the tall grass, Oak encounters a wild Pikachu and immediately catches it before leading the player back to his laboratory.
- Instead of giving the player and Blue the choice between Bulbasaur, Charmander, and Squirtle, Professor Oak tells player to take the single Poké Ball on his desk, containing Eevee,
but Blue shoves the player out of the way and takes the Poké Ball instead. Oak then gives the player the only Pokémon he has on hand: the Pikachu he has caught before, which, after the first battle against Blue, immediately breaks free from its Poké Ball and follows the player on foot from this point onward.
- The old man in Viridian City now must be spoken to before going to Viridian Forest. He attempts to demonstrate how to catch a Pokémon, fails and leaves to get more Poké Balls from the Viridian Poké Mart. The player can visit the Poké Mart to ask him to repeat the tutorial.
- Jessie and James appear throughout the game, replacing Grunts from the previous games in four different places. They are involved in Team Rocket's scheme and are typically found before a battle with Giovanni. Though they are named "Rocket" like any Team Rocket Grunt, they have distinct overworld and in-battle sprites.