No more health; energy and wounds become more important

[Rias]

The idea of having 'energy' (or fatigue) and 'health' as separate resource pools didn't make much sense, so some changes have been made.

"Health" is no more.

Taking damage will now negatively effect your energy, causing fatigue. If your fatigue becomes too great (a tier beyond 'exhausted') you will fall unconscious, and be unable to use most commands. While unconscious, your defense will be a flat 0 (all attacks are guaranteed to hit you) and melee attacks will always inflict maximum damage. While unconscious you will be considered resting, and you will regain consciousness once your energy levels come back out of the negative, be that from natural energy regeneration over time or via external healing, such as a monk casting healing spells on you.

Energy regeneration is dependent on nutrition - energy regenerates only as much as it can draw from your nutrition pool. If you are out of both energy and nutrition for too long, you will die, so don't allow yourself to fall unconscious on an empty stomach!

Since the vague 'health' resource is no more, wound severity is now what causes death. If you have a severe enough wound to your head, neck, back, chest, or abdomen, you will die, so you'll want to keep an eye on your wound levels and make sure they don't get too severe.

Regarding combat: If you can beat a foe into unconsciousness, it's a simple matter to target a vital area such as the head (via the aim verb: aim head) and hack away at them while they're defenseless in order to kill them off completely. Bodiless nether beings (shades, ghosts, wraiths, etc.) and most constructs (animated skeletons/corpses, golems, etc.) will 'die' when they run out of energy, rather than falling unconscious.

[Rias]

Small but important addition: If your energy goes too low into the negative, this will also cause death.