Decent execution of a simple concept. I think one easy improvement would be to cut down on the excessive number of particles. There are dots flying all over the screen, it makes it hard to track the ones that are actually important. I would also lower the difficulty at the start. I think my game has this issue as well (a lot of jam games do, it's tough to judge how hard your game is since you made it, of course you're gonna be good at it), but I think right now it is challenging to the point of being somewhat inaccessible.
I like the cute graphics, the sound is pretty nice, and I am a sucker for bats. Keep it up!