The game wasn't too bad, I feel like there are a few things you can improve though.
-The movement felt a little stiff since there was no acceleration or deceleration (though my game didn't do this that well either)
-A slider to indicate how much longer the cooldown for shooting is would be nice
-Some sounds and background music would be nice, I don't think I heard any while playing
-The background seemed a little bland and empty, maybe there could've been a darkened version of bricks with a few torches
-Killing enemies didn't really feel satisfying enough, maybe there could've been a squishing or dissolving animation when they died or maybe even bones that dropped to the ground