This games fun, but there are deal breakers.
Collision sizes feel weird. And there is the focus function but it feels weird with bullets passing you like its nothing and there's no indication on where the center is other than focus. I'd rather have the image match the collision size.
Everytime I reach the bossfight and die I don't restart at the bossfight. I restart all the way at the back! AHH Please implement a savesystem so I can fight the boss already.
Also random colors on the bullets were interesting! but please set a cap so that only light colors are generated on the bullets. If the colors are dark then I can't see them.
I'm not going to go in detail with the bugs because its obvious people mentioned those already!
Other than that very fun game! Fun visuals! Very easy to get into! And you were creative trying a lot of interesting things! At least with some feedback you can figure out what worked and what didn't! Thanks for the fun game and your creative ideas!