Pokémon: Every Gen 1 Game Ranked

Yeah, the Japanese version of Pokémon Yellow is technically different from the version we got in the west.

Generation one is the only real-time that this happened, if you play the Japanese version of any game from generation two onwards it'll be the same game as the western counterpart, it's just that Pokémon took a while to come to the west with every new version building upon the last entry to enough of an extent to be regarded as a separate game by weird people on the internet like me.

So what makes Pocket Monsters Yellow different from Pokémon Yellow?

Pokémon Yellow came out after the Game Boy Colour whilst Pocket Monsters Yellow didn't.

Because of this, Pocket Monsters Yellow has a yellow colour palette over the entire game if you play it on the Game Boy Colour similarly to how Pokémon Red, Green, and Blue work whilst Pokémon Yellow has a completely custom colour palette that easily makes it the definitive gen one experience.

The only reason to play Pocket Monsters Yellow over Pokémon Yellow is if you really like the colour yellow. Or you know, you're Japanese.