Bigger Boxer
To make your boxer bigger press: Up-C, Down-C, Up-C, Up-C. Then your boxer will be slightly taller than usual.
Big Gloves
Pause the game and enter this code: Up-C, Down-C, Up-C, Up-C, Down-C. A bell confirms correct entry. To deactivate, simply re-enter the cheat code.
Big Head
Pause the game and enter this code: Left-C, Right-C, Left-C, Left-C Right-C. A bell confirms correct entry. To deactivate, simply re-enter the cheat code.