During gameplay press [`] to open the console, then type in:

 addcash           - Get some cash
 nextmission       - Complete mission
 failmission       - Fail mission
 rock              - Enable god mode
 god               - Enable god mode
 gimmeallmissions  - Enable cruise mode
 freecam           - Enable fly mode
 jump              - Press [LShift] to jump
 speed             - Press [LShift] for turbo boost
 teleport          - Press [R] to teleport to random locations
 cameraeditor      - Show cameras
 carcamedit        - Move camera
 setlight          - Show light settings
 shownodes         - Show nodes
 showsounds        - Show sound-lines
 exit              - Exit game