The original Western release of Pokémon Stadium allowed battles using all 151 Pokémon from Pokémon Red, Blue, and Yellow.
Pokémon Stadium was a Nintendo 64 battle-focused game released in Japan in 1999 and in Western regions in 2000. It presented Pokémon battles with 3D models and animations, a major visual contrast with the sprite-based Game Boy games. Players could also connect compatible Game Boy cartridges through the Transfer Pak.
The Japanese release history can cause confusion: Japan had an earlier, Japan-only title called Pocket Monsters Stadium, which used a limited selection of 40 Pokémon. The Western Pokémon Stadium was based on a later and expanded version, so its roster covered the complete original Pokédex.
The game included four Cups, Gym Leader Castle, rental Pokémon, and multiplayer battles. Its successor, Pokémon Stadium 2, expanded compatibility to include the 100 Pokémon introduced in Gold and Silver.