So I took some photo of the game displayed on CRT, looking for the light conditions and color saturation that could make me get a result close to that old picture you showed. Certainly I can't replicate the conditions of the time, also because I'm using a latest generation CRT connected via composite video etc, however I got the result that I was attributing to the use of dithering on a real CRT.   Now, as I said earlier, I'm not saying that there were never any differences between th