Cheat Mode
Go to codes at the options menu then type the code in:
Cheat Effect
Phillips Exeter One Hit Fist Kill
Sacred Feminine Double Health
Vitruvian Man God Mode (infinite health)
Apocrypha All Visual Database entries Unlocked
Et In Arcadia Ego All bonuses Unlocked
Clos Luce 1519 Level Select
Royal Holloway One Hit Weapon Kill

These can be entered by entering the codes menu in
the game:

Et In Arcadia Ego All bonuses Unlocked
Apocrypha All Visual Database entries Unlocked
Sacred Feminine Double Health
Vitruvian Man God Mode(infinite health)
Clos Luce 1519 Level Select
Phillips Exeter One Hit Fist Kill
Royal Holloway One Hit Weapon Kill