Single Player Cheat Codes
     Open  the  console  during a single player game by pressing CTRL,
ALT and ~ at the same time. Then type the following command:

net_allowcheats 1

     Afterwards, you are free to input any of the following cheats for
desired effects. Note that those cheats only work in single player.

Cheat code:        Effect:
give ammo           Gives you some ammo 
give health         Gives you some health
god                 Infinite health, you have to type this 
                    everytime you respawn, re-enter to disable
noclip              Makes you go through walls, re-enter to disable
g_maxproficiency 1  Promotes you to maximum rank 
                    and unlocks everything, 
                    enter g_maxproficiency 0 to disable 
pm_thirdperson 1    Third person view, 
                    enter pm_thirdperson 0 to disable

* Some codes many not have an effect until next re-spawn