Descent, but there are some things that really keeps this back from it's full potential.
First of all, the most critical part of this game - level design - is not very good. I have played until level 52 now, and most of the levels were very easy. Most of those that took some time I just kinda cleared without getting any satisfaction. It was no "Yes! I figured out the trick!" but more like "ok, now i reached the goal somehow"
Second, the physics is really annoying. You really should reduce the intertia.
The graphics are ok, but could have been better. I do like pixel graphics, so it's not that.
Music is good.