Here are some cheats and tips for the game Sonic Heroes.
Two player Team Battle mode:
Collect 20 emblems in single player story or challenge mode.
Two player Special Stage mode:
Collect 40 emblems in single player story or challenge mode.
Two player Ring Race mode:
Collect 60 emblems in single player story or challenge mode.
Two player Bobsled Race mode:
Collect 80 emblems in single player story or challenge mode.
Two player Quick Race mode:
Collect 100 emblems in single player story or challenge mode.
Two player Expert Race mode:
Collect 120 emblems in single player story or challenge mode.
Shiny characters:
Select one of the two player modes, then hold A + Y until game play begins.