Cool visuals and music, a very smooth experience. As others already suggested, it gets a little boring at the beginning, so adding some other elements like a store and a good balance between defending off the glitches and letting them in would probably turn this in an even better game. Also consider a mobile version, it seems to be the right game that you can easily play on mobile just with touch (it probably works already with the Web version, but Web on mobile unfortunately sucks).