Complete the Finale: Ephemera mission, then pause game play, then activate the following cheats by entering the corresponding codes. Note: Only one code can be enabled per mission:
CHEAT FUNCTION - CHEAT CODE Invincibility - Press RIGHT(2), DOWN, UP(2). Note: Stealth kills will do 50% damage. One hit kill mode - Press UP(2), DOWN, RIGHT, UP. Note: You and all NPCs die in one attack. Restore health - Press UP, RIGHT(2), DOWN, LEFT. Unlimited items - Press DOWN, LEFT, RIGHT, UP, DOWN.