Debug mode:
Hold L2 or R2 and press Left, Up, Up, Triangle, Right, Square, Left, Triangle, Up, Down, Right, Right.

Invicibility:
Hold L2 or R2 and press Right, Right, Left, Triangle, X, Up, Circle, Left.

Infinite spirit spells:
Hold L2 or R2 and press Left, Triangle, Left, Left, Circle, Left, Triangle, Right, Circle, Up, Up, Down. Repeat to get new spells.

GameShark Codes

Enable All Levels	800c4704000f
 
Extra Health		d006981ea4c2
			8006981e2400


Extra Spell Ammo	80091c240001


Infinite Lives		800803462400

Thanks to Revolution readers Michaelbk1, Treah, and Ivan Santos!