Someone else posted a similar screenshot, after installing the full game and getting an error message about there not being enough room for textures (
Odd Graphic error). Of course that doesn't mean the issues are related...
Did you try a clean re-install of the demo, and shut down all non-essential programs (especially anti-virus) before re-installing?
I don't know if low video RAM could cause this problem.
For those of you with graphical problems
