Great game. It felt pretty well polished, and the difficulty curve was well implemented. My only real criticism is that I really wish there was a way to make the game bigger on desktop. A couple times I ended up selecting a bunch of text and scrolling my browsing window by clicking outside of the game while trying to jump. And I guess some of the hazards on normal mode didn't really feel all that dangerous, and even helped me a few times, though that's an extremely minor point.
Overall, gameplay, art, and sound design were all very good, and I liked the touch of having mouse's model change as you made progress.