To activate a cheat, press [Shift] + [?] and enter its corresponding code.

Cheat                             Code
All keys                          KEYS
Ammunition                        AMMO
Clear surrounded by 4 squares     ZAP
Debug mode (OFF)                  +DEBUG
Debug mode (ON)                   -DEBUG
Full health                       HEALTH
Gems                              GEMS 
Illuminate room                   -DARK
Obfuscate room                    DARK
Torch                             TORCHES