All levels:
At the screen in the beginning with the 3 skulls, press L1, R1, Triangle, Triangle, Square, Circle, R1, L1. Now go to the load game screen and all of the levels will be listed.
GameShark Codes
Black Spirit Sword 800c6c5c000a Gold Key 800c6cec018e Infinite Antidotes 800c6cc80a0a Infinite Arcs of Power 800c6cb00a0a Infinite Blunderbuss Ammo 800c6c880a0a Infinite Bombs 800c6c7ca0a Infinite Charms of Icy Cool 800c6cd40a0a Infinite Fireballs 800c6ca00a0a Infinite Fireflies 800c6c980a0a Infinite Firethrower Ammo 800c6c780a0a Infinite Flame Lance Ammo 800c6c800a0a Infinite Gold 801afefaff1b Infinite Greater Razor Spells 800c6cac0a0a Infinite Grenade Launcher Ammo 800c6c840a0a Infinite Health Potions 800c6cc40a0a Infinite Infernal Device Ammo 800c6c8c0a0a Infinite Invisibility 800c6ce00a0a Infinite Jet Spells 800c6ca80a0a Infinite Magic Charms 800c6cdc0a0a Infinite Razor Spells 800c6ca40a0a Infinite Speed Potions 800c6cd00a0a Infinite Star Spells 800c6c9c0a0a Infinite Strength Potions 800c6ccc0a0a Infinite War Pigs 800c6cb40a0a Infinite Warding 800c6cd80a0a Magic Warhammer 800c6c68000a Red Key 800c6cf4018e Red Sword 800c6c58000a Silver Key 800c6cf0018e Silver Sword 800c6c60000a Venom Sword 800c6c64000a Warhammer 800c6c50000a
Thanks to Revolution readers Nick Gomez and Joe McGimsey!