Nice game.
1, The game's interpretation of the theme is pretty bad, because if only the enemies can join together, then It is optional and not fun.
2, I think different bodies bullet count should very and not just be 15. That way, there is more strategy.
IE slimes have 5 bullets, regular enemies have 15 bullets and Big Enemies have 25 or something.
Besides these, nice game.
I would be very happy if you would play my game.