Toggle slow-motion:

While playing as Max, hold [Fire] and press
[Equip Up] four times. If you entered the code
correctly, a message will appear. 


Cheat Codes:

While playing a game, press ~, then type one of
the following codes at the "Omen" prompt to 
activate the corresponding cheat function:


RESULT          CHEAT CODE 

God mode        mdkGobSetDamageFilter(mdkGetPlayerGob(),0)
Toggle God mode GodDebugToggle()
Level 1         mdkNewGame(1,12)
Level 2         mdkNewGame(2,12)
Level 3         mdkNewGame(3,12)
Level 4         mdkNewGame(4,12)
Level 5         mdkNewGame(5,11)
Level 6         mdkNewGame(6,8)
Level 7         mdkNewGame(7,11)
Level 8         mdkNewGame(8,8)
Level 9         mdkNewGame(9,13)
Level 10        mdkNewGame(10,7)
Level 10/first bonus     mdkNewGame(11,1)
Level 10/second bonus    mdkNewGame(12,1)