I also noticed the game's acronym!
BTW, thanks for supporting the arrow keys for movement. A lot of developers only impliment WASD and I personally find using my right hand for movement more comfortable.
As for another way of displaying enemy health. I like the simplicity of the game graphics at the moment. Adding health bars to everything would clutter the view I think. A couple of options I can think of are:
Only show a healthbar for enemies that are injured.
Change the colour of the enemies to indicate how damaged they are.
Fade out the enemies as they get more injured. Perhaps keeping a solid outline with just their fill fading.