Big Head Mode
Pause the game and press L1 + L2 + R2 + Down.
Level Select
Pause the game and press R1 + Square, Triangle, Circle, X.
All Sphere Mode
Pause the game and press L1 + L2 + Circle + Square.
Unlimited Health
While playing, pause the game then simultaneously press Circle+Square+Right, then simultaneously press R1+R2+Left.
Passwords
1st Moon - XSXSSCSC
2nd Moon - CXXTCCXT
3rd Moon - CTSCSSTT
4th Moon - CXXXTCTT
5th Moon - XXSXSSTC
Play as Cyborg Blake
Pause the game and press R1 + R2 + Triangle + Circle.