Go to the game file and open with notepad: single\data\config\autoexec.cfg
Then add these to the end of the file:
Then save the file. You must Start a new game for these to work. Your weapon ammo won't drop or your health. The enemies will also ignore you. Remove any of these codes if you wish to not have their effect.
(supplied by: thegrube, KingDaniel)
Unlimited Health, Unlimited Ammo, Save/Load Position (Teleport). Made exclusively for Cheat Happens. WRITTEN FOR THE ORIGINAL RETAIL VERSION OF THE GAME. May not work with all versions. Read the included readme file with Notepad for important instructions on using the trainer. This trainer features customizable hotkeys.(Downloads are on an external site and open in a new window)