All default boxers and arenas
At the main menu, hold R and press Right, Down, Up, Left, Up, L. Note: This does not unlock Mickey or the Rocky Statue.

All default boxers, arenas, and Rocky Statue
At the main menu, hold R and press Right(3), Left, Right, L.

All default boxers, arenas, Rocky Statue, and Mickey
At the main menu, hold R and press Up, Down(2), Left(2), L.

Double punch damage
At the main menu, hold R and press Right, Down, Left, Up, Left, L.

Double speed boxing
At the main menu, hold R and press Down, Left, Down, Up, Right, L.

Full stats in tournament and exhibition modes
At the main menu, hold R and press Left, Up(2), Down, Right, L.

Full stats in movie mode
At the main menu, hold R and press Right, Down(2), Up, Left, L.

Win fight in movie mode
At the main menu, hold R and press Right(2), Left(2), Up, L. Press Black + White during a fight in movie mode to automatically win.