Invincibility: 
Pause the game and press DOWN, CIRCLE, 
SQUARE, SQUARE, UP, X. 

Level Select: 
Start a game on Easy. Pause the game and press TRIANGLE, 
CIRCLE, CIRCLE, LEFT, CIRCLE, UP, DOWN. A Level Select entry 
will appear on the Options menu. 

Unlimited Hearts: 
Pause the game and press LEFT, UP, X, SQUARE, UP, DOWN, 
SQUARE. The heart stone count will increase to 80, and it will 
not go below it.