Alt Enter to get to fullscreen is having the awful effect of rendering many objects jet black, with no depth. the effect makes these objects look like 2d cutouts in the 3d world. Interesting in a way but I'm betting unintended. Switching back to fullscreen doesn't fix it. If you shine a lightsource long enough on them they seem to come back, until you walk away (the problem appears to have something to do with ambient light but that's guessing).
I have a pretty high end card, latest drivers, proper DX, and so on. I've actually seen this for the past couple of weeks or so but figured a patch would fix it, but it seems to be persisting.