Never tried the demo...but it's better than i thought it would be! I read some pretty average reviews about it in recent weeks so wasnt that bothered about playing it. Seems very similar to the first (which is a good thing i think) but with much better graphics and what seems to be (so far) a much more interesting story.
I seem to have sorted the quitting to desktop problem...i set my desktop and in-game resolution both to 1024x768. Hasnt crashed out since. Weird.