After you beat the first level, you'll be able to visit the Sage. He'll be on the second level of the inn. Once he's there, you can visit him at any time to replay levels you've completed, or see "Rewards" you've unlocked along the way.
Full health power
At the "Press Start" screen, press X(4), Square(4), Circle(4). Health: power-ups will all be 100%.
Health Items Restore 100% Life
On the title screen, press X, X, X, X, SQUARE, SQUARE, SQUARE, SQUARE, CIRCLE, CIRCLE, CIRCLE, CIRCLE.
Invincibility
On the title screen, press SQUARE, CIRCLE, X, SQUARE, CIRCLE, SQUARE, X, CIRCLE, X, SQUARE, CIRLCE, X.
Invincible Rau
At the "Press Start" screen, press Square, Circle, X, Square, Circle, Square, X, Circle, X, Square, Circle, X. If you entered the code correctly, Rau will say "Faahu". Enter the "Cheats" section at the Sage, and the last card will be Invincible Rau. Press X to activate the code.
Manual animation
Flip through the pages of the instruction booklet from the back to the front. There is an animation of Rau performing a stealth kill in the lower right corner.
Stronger Opponents
At the title screen press: X, Circle, Square, Square, X, Square, Circle, Circle, X, Circle, Circle, X.
Turn of Arena AI
To turn off the Arena AI, go to the title screen and press these buttons: X, CIRCLE, CIRCLE, CIRCLE, X, SQUARE, SQUARE, SQUARE, X, CIRCLE, SQUARE, X.
Unlimited Arrows
At the title screen press: X, Circle, Square, Square, X, Square, Circle, Circle, X, Square, Square, X.
Unlock Battle Arenas
Complete all of Baumusu's Challenge for a Level to unlock that particular Level's Arena.
Unlock Costumes and Extra Art
To get Costumes and Extra Art, you have to beat the arenas, which means completing all of the arena challenges for both time attack and body count.
Weak Opponents
At the title screen press: X, Circle, Circle, Square, X, Square, Square, Circle.
Weapon Selection
Find each Tuku on all levels to unlock the ability to use any weapon on any level.