The newest addition to the Game Boy Pokémon series, this time with the game based on the T.V. Show. This game is quite similar to the Red and Blue games, but with a twist: Pikachu, whom you get to start out with, follows you around on the screen. You can check his mood at any time. Also, Jessie and James, characters form the TV show, make cameo apperances in Pokémon Yellow.
Just a few differences in this game...
You may notice that the view of the signs and the water are upgraded.
Brock's Pokémon are at slightly lower levels than in Red and Blue... after all, you do start out with Electric-type Pikachu.
Jessie and James, part of Team Rocket, will fight you periodically and send out who else but Koffing, Ekans, and Meowth.
Gary starts out with an Eevee. Lose the battle at the lab and his Eevee will become a Vaporeon. Lose or skip the battle west of Viridian City and his Eevee will eventually evolve into a Flareon. Win both battles and his Eevee will become a Jolteon.
Weedle, whom you can find in both Red and Blue, is not in the wild in Pokémon Yellow. Neither is Koffing and many other Pokémon. But...
Farfetch'd can be found in the wild in Pokémon Yellow!