The health bar was something we were conflicted about at the time. But the last few days, I've been in the mines improving the game properly.
Also, when you die at a boss, you restart at that boss. That was a last second compromise we did to ensure the game was at least beatable. That other boss is the same thing too (Daimon)
This polish update should be out in a day or two, and one thing that we definitely have is a boss Health bar, as well as other stuff. I'll actually show what I've been up to in the dev server. Thanks mate