Mech players: Press Left, Right(3), Down, Up, Down, B, X at the "Join Team" screen. Legionnaire players: Press Down, Left, Down, Right, Down, Up, X, B at the "Join Team" screen. Big heads: Pause game play, then press Up(2), Right, Down, Left, Right(2), B, X. Small heads: Pause game play, then press B(2), Down(2), X(2), Up, Left, Down, Right. Master code: Press Up, Down, Up, Left, Down, Right, Up(2), Down, Left, Right, Left, Down(2), Up, Left(2), Right(2), X(2), Left, Down(2), Up, B at the credits screen.