Enter them in at anytime during the game at the pause screen:
Sword Upgrades: Hold L1+R1 Circle, Square, Circle, Triangle, Triangle, Square, Circle, Square
Complete Current Mission: Hold R1 and enter Square, Square, Square, Circle. Let go of R1 and Hold L1 and enter Triangle, Triangle. Let go of L1 and Hold R1 and enter Square, Square.
Big Heads Mode: Hold R1 and enter Triangle, Triangle, Triangle, Triangle. Let go of R1 and hold L1 and enter Triangle, Triangle. Now hold L1+R1 and enter Triangle, Circle, Triangle.
