The health bar was added to ensure that you would have some feedback when you're getting hit and the animations from the enemies should be somewhat in sync to when you get hit.
As for the feeedback on the enemy, unfortunately I had to choose between correcting some bugs or providing that feedback with the little time I had left and, although I still had a few minutes left prior to submitting the game, I didn't want to trigger a new bug that might have broken the game! But something to consider on a finalized version of the game :D