Start the game with the "-DEVMODE" command line parameter. Then, press
one of the following keys during a game to activate the cheat function.
Note: When in developer mode, all levels will also be unlocked.

Result                          Key

Toggle invincibility          - [Backspace]
All weapons                   - P
999 ammunition                - O
Spawn point                   - [F3]
Toggle no clipping            - [F4]
Move to next checkpoint       - [F2]
Save current position         - [F9]
Load current position         - [F10]
Toggle extra information      - [F11]
Toggle first annd third view  - [F1]
Increase speed                - [Equals]
Decrease speed                - [Minus]
Return to Default speed       - [F5]

Start the game with a shortcut with the following command line parameters
to activate the corresponding cheat function.

Note: Enabling the "God mode"
or the "Unlimited ammunition" codes before the tutorial is completed (which
is after you have delivered the tape to the church) will glitch the game

Effect                                Command line parameter

God mode                             -GameProfile_GodMode 1
Skip introduction sequence           -GameProfile_SkipIntroMovies 1
Unlimited ammunition                 -GameProfile_UnlimitedAmmo 1
Weapons never jam                    -GameProfile_UnlimitedReliability 1
Unlock all weapons for current area  -GameProfile_AllWeaponsUnlock 1