In the single player game

press the pause button and select Option
Select the extra CHEAT option ENABLE is open DISABLE is closed. Effect at a glance 2 computers: CODNoir changes the game screen to black and white. 4 computers: Photo-Negative in-game screen inverse color black to white white to black and so on 6 computers: SuperContrast contrast increase can be mixed with the first two effects 8 computers