Enter the following during gameplay:

ww2god     	God mode
ww2blood   	All weapons and items
ww2showmap 	Full map
ww2clip 	Toggle clipping
ww2rate		Display framerate
ww2debug	Debug mode
ww2level### 	Skip level, where ### is episode and level.

Thanks to Revolution readers Chris Crosby and Zameer Yusof!