This is by far the best combat system I've seen. I love how you took the theme to link the energy with health, that makes for a really unique mechanic. The graphics are perfect, and oh god the use of post processing and the effect when you're low on health is so, so well done. Bravo.
The only thing I would say is that sometimes the player can get stuck on a wall cornered by enemies, and since you can't seem to attack downwards it's easy to get stuck. Other than that though, this is a brilliant submission!