I just checked and confirmed both 800x600 16-bit DirectDraw 7 and 1920x1080 32-bit 60 Hz DirectX 9 modes selected with f1_res_config.exe work for me without any colour corruption, however I have experienced the same issue you have detailed with Killap's RP and it was caused by one of the video rendering modes in Sfall. I don't have this problem anymore so it was either fixed in a newer version of Sfall (there is a much newer version available ie 4.0.7 on GitHub) or it was fixed in the GPU driver by NVIDIA. Are you using AMD? Looking at the ddraw.ini for Sfall there is a comment the Graphics section which states "IT IS NOT RECOMMENDED TO CHANGE "MODE" FROM 0 (8 bit), USE F1_RES INSTEAD; CHANGING MODE HERE MAY RESULT IN CRASHES IF USING F1_RES". I didn't notice any increase in visual fidelity when increasing the colour bit depth from 16-bit to 32-bit so I would keep it as 16-bit. I think the only setting you should change is the Output Mode from DirectDraw 7 to DirectX 9. Have you tried updating to the latest GPU driver cleanly, by removing the leftovers with DDU?