Pretty good game! The unstable platforms are a nice use of the theme, and I really liked how much of a double edge sword it was for both the player and enemies (I can't imagine getting enemy navigation right was easy, but it turned out great).
I have mixed feelings on the respawn/continue feature. I get that it's there to keep the game from being too frustrating, and I do appreciate that, but as it stands its way too forgiving and took a lot of the excitement out of the game. Maybe you could have a limited number of lives, or a level system, or have respawns cost points, just something that actually punishes the player for rushing bosses with the shotgun without caring about bullets.
Other than that, this is really well done!