Well I think it's a great little piece - it looked well planned and it was well executed. Your choice of camera angle, and the continuity were very professional. It had atmosphere - dark and broody - a moving cam gives a constant feeling of impending menace. Your "shock crash" came at the perfect moment, just as the tension was dropping.
Don't think I could suggest how to improve this. For me, the ending was a bit of a letdown, though. Don't really get it - is it that the "demon" is in his own head - and thus inescapable?