A few issues
1. There is no feedback when you get hit. Play a sound or shake the screen to give the player a little feedback
2. There is no pause menu, which makes it a little hard to leave or, well, pause when you have to step away.
3. Falling off the map was a bit interesting, because I couldn't see.
4. More of a bug really: when you die, the game will occasionally not capture the cursor again.
However, it's quite fun, and there is a solid amount of body to the game regardless of the bugs and/or missing features.