Dark Omen being one of my favourite games from youth, I've tried to replay it.
After following this Help Section - I've managed to run it on CPU mode. Althrough CPU mode sucks greatly. I've tried to play with it, but I can't - it just looks so much worse...
when I do start Dark Omen - intro play fine (normal colors, resolution, etc) but when intro ends (or I do interupt it) then game hangs - I do hear menu music, but on screen it is either frozen intro (if I interrupt) or black screen (if I let intro run till the end).
If I go for registry and set SoftwareSelected = 228, then game start fine but with CPU mode with 3dmode being unselectable. If I delete SoftwareSelected then well no luck - intro hangs or black screen if I let it run till the end.
For now I only have access to Intel HD GT1 (it is Haswell generation, so same generation as 4400 / 4600 / 5000) and from my experience it runs all games that Intel hd 4000 / 4400 can.
PS. Additional question - now I can't afford it, but maybe sometime in future I'll be able to afford other GPU, and so I've heard that Nvidia users can use 3dmode. What about AMD/ATI cards relatively new cards? (7xxx or r5/r7/r9 series)?