Pokémon Stadium 2 is a 3D Pokémon battle game on Nintendo 64, developed by Nintendo and HAL Laboratory. The sequel to the first Stadium, it works with the Generation II games and was released in Europe on 19 October 2001. Here is its fact sheet.

The Pokémon Stadium 2 box.
Japanese titlePokémon Stadium Kin Gin
PlatformNintendo 64
Japan release14 December 2000
North America release26 March 2001
Europe release19 October 2001
PublisherNintendo
GenrePokémon battles, mini-games
Players1 to 4
Pokémon251, including 246 as rentals
AccessoryTransfer Pak, sold separately
Compatible gamesRed, Blue, Yellow, Gold, Silver, Crystal

The modes

ModeContent
Battle Now!An instant battle with a randomly picked team, Lv. 40 in Round 1 and Lv. 70 in Round 2.
Event BattleA two-player battle with their Game Boy teams, under the rules of a cup or your own.
Mystery GiftA daily gift for Gold, Silver or Crystal.
StadiumFour cups: Little Cup, Poké Cup, Prime Cup and Challenge Cup.
Gym Leader CastleThe Johto and Kanto Gym Leaders, the Elite Four, the Champion and Red.
Free BattleBattles in the unlocked Gyms.
Pokémon AcademyLessons, tests and a strategy library.
Pokémon LabThe 3D Pokédex, the boxes and the trading machine.
Mini-gamesTwelve mini-games, a quiz and a championship mode.
My RoomThe room from Gold, Silver and Crystal in 3D.
Game Boy TowerGame Boy games on your television.

The details are on The Academy and the other modes.

The Japanese Stadium

In Japan, a “Mobile Stadium” feature let you replay in 3D the online battles of Pokémon Crystal, downloaded through the Mobile Adapter. It does not exist in the Western versions.