Great fun. Simple game, but very fluid.
A couple of points of feedback:
The controls are not super intuitive. I would much rather use "w" for jump, and "space" or "mouse1" for attack.
As we are given a limited amount of space on the screen to dodge, it would be great to be able to change direction in mid air. That would be more of a nice-to-have than need-to-have.
That said, I had a good time, and could totally see playing it for hours. The control (shoot vs. jump) was the only piece that really pulled me out of the game.