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Most playable characters in a platform videogame

Most playable characters in a platform videogame
Who
SEGA, Sonic Heroes
When
2004
Sonic Heroes by Sega, released in 2004 for the GameCube, PlayStation 2, XBox and PC, has 12 playable characters - a record for platform games.

Players compete in four teams of three: Team Sonic features Tails and Knuckles; Team Dark features Shadow, Rouge and E-123; Team Rose features Amy, Cream and Big; and Team Chaotix features Espio, Charmy and Vector.