In Duke Nukem Forever for the PC, PS3 and Xbox 360, there are several cheats you can unlock in the Extras menu when you beat the game on any difficulty.
Here is the list of cheats you can unlock in the cheats menu:
- Concept Art
- Development Timeline
- Duke 3D Freeze Ray
- Duke Sound Board
- Grayscale Mode
- Head Scale
- Infinite Ammo
- InstaGib Mode
- Invincibility Mode
- Mirror Mode
- Movies
- Screenshots
- Triptych Office Photos