My original idea for the enemies health system in the game was to use an immersive black and white health system to indicate the enemies remaining health. This was to keep in with the idea of having no visible HUD.
As you can see around the enemy the world is rendered in black and white. The larger the B&W area is, the higher it's health will be. As you attack the enemy it's the B&W radius will start to shrink and when it no longer turn any of the world B&W it will be defeated. However to be able to render the the B&W effect, you need to enable a thing called WebGL. Unfortunately mobiles cannot render WebGL and I won't be able to use this for the iPad version of the game and will have to resort to using a regular health bar and will keep the B&W health for the PC/Mac browser version of the game.