If you get tired of having Jen turn into a thirty day special (i.e., die), press START once to go to the New Game/Load Game/Options screen. Hold L1 + L2 + R1 + R2 for five full seconds to call up the cheat box. To input cheats, you need to highlight a cheat line and hold X. Press LEFT or RIGHT to cycle the letters. Pressing LEFT or RIGHT without holding X will select the next or previous letter. Press SQUARE to activate the cheat, then press TRIANGLE to exit the cheat box.

Input MONSTROUS on the Invulnerability line.