Great game! It's amazing how much content you managed to add in such a short timespan, not just the three bosses but also the levels of difficulty. Love the visual style especially.
I think it's a great interpretation of consequences that the enemies you let escape return during the boss fight, although I only noticed when I reread the description after playing (I was busy dodging bullets and not particularly paying attention to the UI or what each number means h)
The powerups were kind of confusing to me, I got the ability to shoot in several directions & lost it again several times but wasn't sure how I got it in the first place. Also the focus (L) did not work for me (browser version)
Overall great entry, definitely one of my favorites so far!