Cheat mode:
-----------
Select "Options", then the "Keyboard" tab, then "Advanced". Place a check
"Enable Developer's Console" then click "OK" or "Apply". Press ~ during 
game play or a the main menu to display the console window. 
Type sv_cheats 1 to enable cheat mode. Note: You can also bind any cheat 
code to a key, for example bind x "sv_cheats 1" to execute the svcheats 1
code by pressing X.

Effect                                      Code	
---------------------------------------------------------------------
Bind command to key                       - bind [key] "[command]"
Set speed; 1 is default                   - host_timescale [number]
Deactivate cheat mode                     - sv_cheats 0
Toggle unlimited Run/PsiForce             - sv_infinite_aux_power [0 or 1]
Refill ammo regardless of inventory       - givecurrentammo
Spawn Scrabouillor at pointer             - npc_create npc_scrab
Spawn Sentry at pointer                   - npc_create npc_turret_floor
First person view                         - firstperson
third person view                         - thirdperson
Third person view with alternate controls - thirdperson_platformer 1
Spawn indicated item                      - give [item name]