Cheat Mode:
     Press  X,  Y, White, Black, X, Y and X at the main menu to unlock
Cheat Mode.

Level Select:
     Press  X,  Black,  Y,  Black,  X, White and Y at the main menu to
unlock level select.

Invincibility:
     Press  White,  X,  Y,  Black,  X, Y and Black at the main menu to
unlock invincibility.

Double Damage:
     Press X, Black, X, Y, X, White and X to unlock double damage.