The game plays an opening logo but immediately after that I get a gray screen. Any updates that fix this?

Hm, maybe you could try to find and manually install OpenGL, though it should be already installed with your GPU drivers.

You can also try to install:
https://www.moddb.com/mods/realrtcw-realism-mod

It could make your game work - this does works for me on Windows 10, and it will make the game better, give it a shoot.