Slow mouse and brightness problem

I bought Arcanum off gog a while ago and after some initial hiccups managed to get it running just fine, and have been playing it without issue for some time now. However, I recently started up the game again and noticed two new problems: the mouse suddenly moves very, very slowly, making the practically unplayable (this slowness is not to due to lag, and the mouse still moves smoothly, albeit very slowly); and the graphics are much brighter and washed out. I tried adjusting the brightness in the options menu, but the option is greyed out and I can't change it. I also tried lowering mouse acceleration, but that didn't work either.

I have the UAP installed, and run the game in windowed mode (reduces lag for some reason). I don't use -no3d or -doublebuffer as they cause severe graphical glitches.

These problems seem to have appeared suddenly and without provocation. The only thing that I can think might have caused this were some windows updates (I run this on windows 8 btw).

Any help is appreciated, thanks.