While playing the game, press Square, X(2), Square, Triangle(2), Square, Circle(2), Square, R3. If you entered the code correctly, you will hear a sound. Although you will lose health you cannot die. Note: This code prevents trophies from being unlocked. To prevent this from happening, enable the code, then quit to the main menu. Select "Continue" or "Replay Mission", and you will now be able to unlock trophies with the code enabled.