In Pokémon Stadium, the Prime Cup is the only Cup that does not originate from Pokémon Yellow's Colosseum 2. Instead, it is based on the regular Colosseum battles, which have no special limitations. As a result, all Pokémon, including powerful Legendary Pokémon such as Mewtwo, are allowed. There are no level restrictions in the Prime Cup, so all of the opponents will have level 100 Pokémon.
This is the only area in the Pokémon Stadium series where the elusive Mew and Celebi can be found. In Pokémon Stadium, the male Cooltrainer will have a Mew during the final battle of the Prime Cup division, while Cooltrainer Marty will have a Mew during the Round 1 Prime Cup in Pokémon Stadium 2. Likewise, Cooltrainer Marty will have a Celebi during the Round 2 Prime Cup in Pokémon Stadium 2. Also, Mew will be available as a rental Pokémon for Pokémon Stadium's Round 2 Prime Cup, while Mew and Celebi will be available as rentals in Pokémon Stadium 2's Round 2 Prime Cup.
In Pokémon Stadium, there are four levels of difficulty: Poké Ball, Great Ball, Ultra Ball, and Master Ball. In Pokémon Stadium 2, there is only one level of difficulty.