Extra mission
If you see all the credits when you complete the game, you will access an extra mission of epilogue.
Cheats
Activate the console in the game options, press the [ş] key to show the console, and then:
Enter: Seta Thereisacow “1337” and click Enter.
Enter: spdevmap bog_a .
Level salt.
Then, a new game begins or loads a saved game, and you will have at your disposal the following cheats:
Give All: All weapons.CG_LASERFORCEON 1: LASER MIRVES FOR ALL WEAPONS.Jump_height #: Adjust gravity (default, 39).Timescale #: Adjust time (default, 1.00).R_Fullbright: easier to see things.Notarget: enemies ignore you.Give Ammo: Mooring to the fullest.God: God mode.Demigod: God mode, but the screen trembles.Noclip: Without collision detection.cg_drawgun: your weapon does not appear.CG_FOV: Zoom with any weapon.