Various cheats
  
Activate Console
     Edit the GameSettings.script file in your install directory using
Notepad. Replace the following line:

bool ConsoleEnabled = false;
with
bool ConsoleEnabled = true; 

Cheat Codes
     Press  [F3]  to  activate the console once in the game, then type
any of the following codes:

Code code:                   Result:
immortal = true              Immortality
god_mode = true              God Mode
unlimited_ammo = true        Unlimited Ammo
fullammo                     Full Ammo
enabled_missions = true      Unlock All Missions

Alternate Codes

Cheat Codes
     Use Notepad to edit the "GameSettings.script" file in InstallDir\
folder of the game:

set bool ConsoleEnabled = true 

     Then,  in  the  game  you'll  be able to bring up the console and
enter following cheats:

Cheat code:                  Result:
SetImmortalMode              God Mode
LoadFullAmmo                 Full Ammo
SetUnlimitedAmmo             Unlimited Ammo