Cheat mode:
Press X, Y(2), X(2), Y(2), Start at the title screen to enable cheat mode. The starting
menu will appear instead of the opening FMV sequence to confirm correct code entry.

Full health:
Enable cheat mode. Then, pause game play, hold L + R and press Right. 

God mode:
Enable cheat mode. Then, pause game play, hold L + R and press Left to enable
invincibility and 50,000 point attacks. 

Level skip:
Enable cheat mode. Then, pause game play, hold L + R and press Down. 

Full pause screen:
Press Start to pause game play, then hold X + Y.