During the game type any of these passages:

WW2GOD
WW2BLOOD
WW2LEVEL### (### is number of level)
ww2clip     (This will go to the walls)
ww2showmap  (Show you full map)
ww2ryan     (You won't Unlimited lives any more)
ww2rate     (I don't know what is this doing)
ww2debug    (This will show you debugger)