I bought this game in Steam and when I started it a grey screen appeared. The sound was on, but no image at all. I tried several times, but it didn’t work.

The fix was to browse the files from the game:

And edit options.ini

The graphical driver can be DirectX or OpenGL but in my case that value was empty.

So I added DirectX, saved, and started the game and this time it worked properly.

Driver = DirectX