Various Cheats
     At  the  start  of  a new game, go to the right until you reach a
teddy  bear. Now face the wall and jump in that direction. Walk to the
next room just to the right of where you are, which will lead you down
to  a  small room. Jump to access a platform, and use this platform to
access  a  playroom where you can turn cheat mode on. Now enter any of
the following "Codes" during gameplay using Controller Two:

Effect          Code
Invincibility   X, X, X, X, Triangle, Circle, X, Square
All Weapons     Circle, Circle, Circle, Triangle, Triangle, X, X, Square
Level Select    Triangle, Triangle, Triangle, Square, Square, Square, X, X,
                Circle