The game feels like a prototype. But over all its not bad. There was a nice verity of enemy's to face. I could see this game working on the mobile platform
Things I felt needed more work:
Ui needs to be standardized so all the sprites look and feel the same
Feedback to the player. For instance knock them back once they take damage so they can just abuse the invincibility
Remove the exit button in the web version it causes a bug
Enhance the HUD. Its hard to see the what heath I have left as the white got lost in the background. a bright read heath bar is standard
And add controller support.

Don't let all this feedback discourage you. Every game starts out as a proof of concept. With a bit of refine the fun of the game will realy start to shine . Goodluck