Well, the original dox for this cheat was poorly informative so I had to find out for myself how to use those codes. And here it goes.

To enter the cheat codes below you need to be in Talk mode. Normal key to get there is T. Once there just type any of the following:

ammo = Gives full ammo
god = Gives god mode
guns = Gives all guns

Enjoy this fun game :)

Credits goes to iND for the original info on the codes. Shame on them though for forgetting to tell us where to use them ;)

/Hel