Hopefully the engine is more optimized this time. I experienced all sorts of odd issues with the original, and judging by the official message boards, so have many others. What's odd is that so many people seem to have experienced so many different problems.
In my case, whenever I viewed any sort of fire, the game would stutter (framerate) despite the fact that FRAPS was still reporting 60 fps. Turns out that the only fix was rolling back drivers to something from late 2007. :\ Very annoying.