Cheat Codes:
During gameplay press ~ to get the console then put in a code below.

Result - Code:

God mode - toggle g_p_god
Suicide - kill
All weapons and items - give all
Maximum ammunition - give ammo
All keys - give keys
Jet pack - give jetpack
Force field - give forcefield
Extra life - give life
10 nukes - give nuke
100 Ego - give health
Mark secret found - give secret
Spawn extra babe - give bomb
Get a kill - give kill
Matrix-style pause - pause
Display map information - toggle g_map_info
Display game statistics - toggle r_stats
Debug mode - toggle g_debug
Camera can explore level - camera camera
Return camera to normal - camera player
View frame rate - toggle r_timings


Cheat Method:
Press ~ to bring up the console then type in
exec cheats.cfg and press ENTER to activate cheats

Now press a letter below

G - Get Everything
H - Max Ammo
J - Get Jetpack
F - Get Forcefield
L - 1 Extra Life
K - Self-Destruct
I - Invinicibility
P - Pause