Invincibility
Press Up, Left, Down, Down, Left, Down, L1, R1, Right, Down, Right at the main menu.

Codes
1. Go to the Main Menu with the three skulls.
2. Press L1, R1, Triangle, Triangle, Square, Circle, R1,and L1.
3. You will hear a sound to confirm that the code worked.
4. Select the "Load Game" skull and the next screen will show all the levels.
5. Choose any of these level and be warped there.