Ok, then the x-ray engine (powering Stalker) provides better lighting, full lights and shadows applied to every mesh, like you can see here:







What a huge difference this makes. But maybe the conversion from the console version of Fallout to PC is the reason for this.
A projection shadow shader would do the job for all the geometry, no matter how many polygons. It is calculated per pixel and needs a depth map for the right projection. There is no pc from the year 2012 needed for that.