For certain missions, you take control of an amigo, automatically assigned in specific stages. Sonic gets the help from Tails and Knuckles the Echidna, Shadow's sidekicks are Rouge the Bat and E-123 Omega, and Silver is assisted by Blaze the Cat and Amy Rose. There are two multiplayer modes: Tag Mode (co-op) and Battle Mode (versus in a race for gold medals). The characters are voiced by the cast of the Sonic X animated TV series.