At the Main menu hold L1 + R1 and press Circle, Triangle, Square, X. If the code has been entered correctly a sound will confirm. 'Level Select' and 'ALL Weapons' will be unlocked at the Options screen and by pressing X on the 'Level Select' option you will be able to access a screen with all the levels and by pressing Triangle you will be able to get to the journal screen to select the weapons including the hidden weapons in the game. The hidden weapons are Glacier Boomerang, Torch Hammer, Doka Pin and Pig Ball
Unlimited Magic: Talk to Kainen who is at the door just before you go to fight the evil last pig and he will give you unlimited magic for the pig robes. This will become useful when getting the Ice Candy for the man in Circus Town.