"Start a new game. Enter the following code at the entrance door:
"120763-090665"
Hold the CTRL and click on OK. Press CTRL + 0 and select to
not save the game.
Open any of you previously saved game file from here, and you
can use any of the next cheat codes:
VRROOM
TAPESTRY
LOBBY
JUNGLE
HALL1
GARAGE
DRUM
DALI
CHASM
CELLAR
ATTIC
After entered any codes, you have to press "ENTER" key to activate
the cheat effect. You'll be warped directly to an another area of
the game.
Transform gun to machine gun:
Hold CTRL and shoot the target rats at the rat shooting gallery.
Hold down the fire button to let off a volley of shots.
When you run out of ammo, you go to another area of the game.
"