Pretty nice experience, I feel like there's some solid foundations here. I would've liked to see some more impact from hitting bullets as shooting feels pretty lackluster right now, and there are some problems with the enemy AI: if you're too far they don't chase you, if you just keep running in a straight line most of them can't harm you in any way. It would've been interesting to give the player some more options (a dash, a special, an ability?), and make the enemies tougher in return. Increasing the skill floor (and ceiling) would make the game a whole lot more fun, in my opinion :)