The names "Pokémon Stadium" and "Pokémon Stadium 2" refer to different games between Japanese and English. Since this game was never released outside Japan, the later game known as ポケモンスタジアム２ (Pokémon Stadium 2) in Japanese had its name adapted to "Pokémon Stadium" in English.
Subsequently, the third game in this series had its name changed as well: from ポケモンスタジアム 金銀 クリスタルバージョン (Pokémon Stadium Gold, Silver, and Crystal Version) in Japanese to "Pokémon Stadium 2" in English.
This game's Japanese title literally translates to "Pokémon Stadium". The game is subtitled with the English subtitle "Pocket Monsters' Stadium". On the official Japanese site for the game, the background image uses the English title "Pocket Monster's Stadium".
All modes except Battle require a Game Boy game saved at a Pokémon Center and connected via Transfer Pak. If a Game Boy game is connected but not saved at a Pokémon Center, the game displays an error message.
Battle (バトル): Players can battle against other humans or computer-controlled opponents.
Organize (せいとん): Players can transfer Pokémon and items between their party, PC boxes, and storage boxes in the game.
List (いちらん): A list of a player's Pokémon and their stats can be examined.
Pokédex (ずかん, or Encyclopedia): Players can view their Pokédex in 3D.
Register (とうろく): A team can be registered.
Party (てもち): The player can examine their current party.
Many of these features were integrated into Oak's Lab in future Pokémon Stadium games.
Battle Mode features two modes: Free Battle (フリーバトル) and Tournament (トーナメント).
In Free Battle, a player can battle against another human or a computer-controlled player under one of three rulesets: the L1-30 Division, the L50-55 Division, or Free Battle, where Pokémon of any level may be used.
Aside from battling with their own Game Boy Pokémon, there are eight pre-configured Trainers that players may use, with Pokémon ranging from level 20 to 100.
L1-30 Division: This tournament is based on the Nintendo Cup '98. There are four divisions: the Monster Ball, Super Ball, Hyper Ball, and Master Ball.
L50-55 Division: This tournament is based on the Nintendo Cup '97. The total levels of the three Pokémon selected cannot exceed 155. The opponents in this mode are based on actual competitors in the 1997 tournament.
Unlike future Pokémon Stadium games, there are no Continues.
The credits roll after a tournament is cleared.
After one of the tournaments is cleared, the player obtains a Doduo Game Boy upgrade that allows the Game Boy games to be played with frame skip at double speed. When both tournaments are cleared, the Dodrio Game Boy is obtained, allowing the games to be played with frame skip at triple speed.
The main menu. An error message that tells the player that the game has not/cannot access game data from a Generation I game cartridge.
Transfer Pak compatibility
There are only 40 Pokémon available for battles. Most of these Pokémon were used in official tournaments, with a few Pokémon added for type balance. Below is a list of the Pokémon that were included in the game.
While the other 111 Pokémon cannot be used in battle, their 3D models can still be viewed in the other modes.
Most, if not all, of the 111 remaining Pokémon were intended to be accessible via the Nintendo 64DD, using a special expansion disk. Due to heavy delays of the 64DD console, this disk was never released. This is also why during the credits, Caterpie, Weedle, Hitmonchan, Hitmonlee, Clefairy, and Jigglypuff are shown battling, even though these Pokémon cannot be used in the game. The final game is still compatible with the 64DD in a technical sense, and even has a floppy disk drive 3D-modeled in the game terminal, but no disk can actually work with it.
If the player clears the Master Ball division of the L1-30 Division with a Pikachu in their party, that Pikachu can learn Surf.
Since this game was only released in Japan, Pikachu can be taught Surf in the international Pokémon Stadium, whereas it cannot in the Japanese version of that same game.
Nintendo's flyer for the retail release of Pokémon Blue
Nintendo advertised Pokémon Blue's compatibility with Pokémon Stadium in a September 1999 flyer for the game's retail release in October 1999. Oddly enough, it does not mention Pokémon Stadium 2, which had already been released in April 1999.
The game's name may be a reference to 64 Mario Stadium, a Nintendo-centric Japanese variety show that featured televised coverage of Pokémon tournaments.
The game was going to have support for the Nintendo 64DD, but the programming was never completed.
The game was going to have team battle support like the English release and sequel, but programming for the function was never completed.
According to a FAQ page that was available in February 1999 on Pokémon.com, there were no plans to release an American version of Pokémon Stadium, as well as any other Pokémon games that have been only released in Japanese at the time. This referred to the first Pokémon Stadium game (the version with only 40 Pokémon available for battles), which was indeed never released in English. The second game in the series was translated in English as simply Pokémon Stadium later (as opposed to the Japanese name Pokémon Stadium 2).
This game is sometimes nicknamed "Pokémon Stadium Zero" outside of Japan to distinguish it more easily from its sequel.