Invincible Rau:
Press Square, Circle, X, Square, Circle, Square, X, Circle, X, Square, Circle, X at the "Press Start" screen. Rau will say "Faahu" to confirm correct code entry. Enter the "Cheats" section at the Sage, and the last card will be Invincible Rau. Press X to activate the code.

Full health power:
Press X(4), Square(4), Circle(4) at the "Press Start" screen. Health power-ups will all be 100%.

Unlimited arrows:
Press X, Circle, Square(2), X, Square, Circle(2), X, Square(2), X at the "Press Start" screen.

Stronger opponents:
Press X, Circle, Square(2), X, Square, Circle(2), X, Circle(2), X at the "Press Start" screen.

Weaker opponents:
Press X, Circle(2), Square, X, Square(2), Circle at the "Press Start" screen.

Disable arena AI:
Press X, Circle(3), X, Square(3), X, Circle, Square, X at the "Press Start" screen.

Weapon select:
Find each Tuku on all levels to unlock an option at the Sage that allows you to use any weapon on any level.

Arenas:
Successfully complete all of the challenges in a level to unlock that level's arena.

Alternate costumes and character art:
Successfully complete all time attack and body count challenges in an arena to unlock alternate costumes and character art.

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.