I liked this game, I enjoyed how the player always rotated to see the boss and how the player health and enemy health were displayed in game as opposed to on a Hud. The game felt intense and had me on the edge of my seat. The boss had a good variety of attacks and was overall really fun.
If you wanted to improve, sound effects and music would be nice. I saw on the game page you put this together in three days, which was super impressive.
Overall, good work!
Check out mine if you get a chance!