I can start SSZ:Director's Cut under WIN 8.1 but as soon as the intro to the first mission plays the screen went grey the first time, with swirls as if it was trying to render something. The second time it's just black but I can hear the music still playing.

Do you use GeForce Experience by any chance? This tool is making some troubles with games lately, maybe it's interfering with SSZ too.

I don't think so, I've never downloaded it although I have an NVIDIA card that came with my laptop.

These graphic glitches are still unsolved, but I suspect them to be connected to NVIDIA, probably the drivers. I've got different hardware on my system(s) so I can't test it.

Yeah it's really disheartening to go to the game dev website and have these issues still unsolved after 2 years or so, it seems. What if I installed the old version, without the dir cut?

Sure, why not. It's almost the same game. The changes to the campaign are rather minor and on a laptop the complexer graphics could result in performance issues anyway. That is if the DC would run at all. If you want to play it now, give the original release a try.