I had a flashback to one of the coolest video games of the early 90s PC era, Aladdin based on the Disney movie. In place of a conventional "life bar", in the upper left corner there was an image of Genie, whose expression would change from happy to concerned to terrified as you lost health. I always thought that was innovative. At a glance -- in less time than it took for your eye to measure the actual length of a health bar and compare it to its potential full length -- you knew with remarkable precision how much more punishment you could take before dying.