Using cheat mode:
Begin your game with the "-console" command line parameter. Push ~ to view the console window, then submit sv_cheats 1 before loading a game or level to enable cheat mode. Submit one of the codes below at the console window to enable that corresponding cheat function.

What the Code does	Code
Unlock God mode	god
Unlock No clipping mode	noclip
Unlocks every weapon	impulse 101
Set gravity; 800 is default.	sv_gravity <number>
Set jump distance; 10 is default	sv_accelerate <number>
Set skill level; 1 is easiest	skill <1-3>
Unlocks Level select (look below)	map <level name>

Level names for the level select code:
Submit one of the entries below with the map <level name> code.

ba_canal1
ba_canal1b
ba_canal2
ba_canal3
ba_elevator
ba_hazard1
ba_hazard2
ba_hazard3
ba_hazard4
ba_hazard5
ba_hazard6
ba_maint
ba_outro
ba_power1
ba_power2
ba_security1
ba_security2
ba_teleport1
ba_teleport2
ba_tram1
ba_tram2
ba_tram3
ba_xen1
ba_xen2
ba_xen3
ba_xen4
ba_xen5
ba_xen6
ba_yard1
ba_yard2
ba_yard3
ba_yard3a
ba_yard3b
ba_yard4
ba_yard4a
ba_yard5
ba_yard5a