Pretty fun, I think the dificulty curve could be a bit more steep since it's pretty easy to get to a point where you're ridiculously OP (not that getting there isn't fun though). I like the visual style too. If you expand on this in the future you could easily add in some enemy variety, maybe some that rush you from behind, etc. Maybe some variety in level geometry too to make evading more interesting. Really good starting point for something bigger though!