Funny how Hue and I allways seem to post roughly at the same time.
Anyway,.. I've tried you game as well and it ran fairly well on my system. I didn't experience any of loading problems. Mouse controls were very fast for me as well. But I was able to correct it with the mouse control options in the menu. Something odd there as every changable option is well above 1.0 at first, but as soon as you change it, it becomes a value between 0.1 and 1.0.

Other than that the game worked great. The boss takes a while to kill though. It appears as if nothing is happening when you hit it, but eventually it died anyway. A sound or some kind or a visible indication that you've hit it (bloodstains?) might help. Also after some time I noticed that its very easy to hit him without getting hit yourself. As soon as it attempts to hit you, simply walk a few steps back and he misses. Perhaps if you make his attack a bit faster, it'll become a bit more difficult.

Very nice work all in all though!