I liked the use of the theme, and the game play is pretty solid.
I always like to give feedback on things that could be improved so here are mine for your game. navigation was a bit tricky when entering tight corridors on a wide wall, the player had a tendency to get stuck if not lined up exactly correctly. I think you are using a square hit box for the player's movement collision, so the simplest way to fix this would be to make the hitbox a circle instead, assuming you don't want to make it smaller.
the other small issue I found was that the player instantly snapped to looking "downward" whenever I wasn't moving them. this made fights just a tad harder because the player could only ever shoot downward when standing still. To fix that I'd check your movement logic and just make sure it's "doing nothing" if no arrow keys are pressed.
other than that great game, nice job, I had a fun time playing it.