This game is really cool. I think the theme you used is one of the most creative out of any other on this jam as of right now. I don't ever usually give games 5/5 but for the theme it's definitely a 5/5.
I guess I don't have any criticisms other than there is a lot of visual noise that my brain starts spinning. It was better with the boss because the background was blank and the bullets felt more spaced out while still being close together, compared to enemies where the bullets were always mushed in with each other and there are like thousand of enemies moving. Which is a shame, it looks like this game has a lot of artistic details with its pixel art, that were hard to focus on because of that.
Although I guess that's a Shmup thing i have to deal with. This game is great.