Pause  the  game  using  [Pause/Break],  then  type  one  of  the
following codes to unpause with the new option:

IAMGOD                  God Mode ON/OFF
GHOST                   Wall Collisions ON/OFF (No-Clipping)
ALLGUNS                 Free Ammo for ALL Weapons
HIDEENEMIES             Enemies/Objects ON/OFF
FPS                     Show Frame Rate