All I get is a black screen no matter what settings I input.

The manual mentions DirectX 9.0c software. I tried to download DirectX upgrades on the Microsoft website but none of them are compatible with Mac, all being exe files rather than dmg.

I'd like to play this game but nowhere can I find assistance for this problem.
There's mention of similar issues on Steam but these are solved either by extensive Nvidia tampering or changes to the Steam console itself so they're no help.

I tried appealing to the GOG technical support but they asked for a DXDiag report which the guide said can only be accessed with the Windows Key + R, which I can't find an equivalent for on a Mac.

I even tried to ask for a refund but I couldn't figure out a way to lodge a request for this.

Please help!

If you have Shadowgrounds Survivor you have to install the Legacy version of Physx (this will not overwrite your up-to-date nvidia instalation)
http://www.nvidia.com/object/physx-9.12.1031-legacy-driver.html

I appreciate the reply!
Where should I put the file in my library to use it though?

Just install and Survivor will work. If you like to keep it for another computer, just archive anywhere you prefer.