This is a simple fix for Demigod which involves disabling one of those annoying shaders whose sole apparent purpose is to create a halo around an object. I could not find any cosmetic improvement from enabling this shader. You can spot it if you look at the edges of the map's floor.
To install, unpack both ZIPs where Demigod.exe is located (bin folder).
No luck so far pushing the interface into depth, will keep trying stuff. This halo shader however was the main 3D rendering problem. For now, on the nVidia scale I would rate the game "Good" (not quite Excellent like the 3D profile says).