A really strong game! 🙂
The visual style fits the minimalism, the different levels each feel different, and the many enemies that felt unique!
It got a little bullet-hell like towards the end, so I was a little worried I would not be able to get to the end (especially because I did not know where the health bar is), but I managed to survive.
The integration of the theme was nicely done, although I did not play any different from a normal shooter, because each bullet was only marginally stronger than the previous. Maybe if the difference were exponential and there were a cool effect on the last shot, I would definitely have chosen more closely where to shoot it.
Perhaps you could also add a scoring system (less bullets used = more score 😉).
Overall, this is one of the most fun games I have played in this jam. Very well done!