Instead of sleeping I decided I should throw this next bit up too.
Now where we had previously left off was discussing my view of hit points and how they work, along with what happens when unfortunate adventurers and mooks run out of them. So, naturally, we must figure out how to go from the prior to the latter.
While I prefer one method of handling hit points, the game itself or even the players may ultimately determine what is what and where. For example, games like Metamorphosis Alpha and Gamma World both assume hit points are a character's physical capacity to survive damage, so we usually would stick to that when playing those. But when I'm having my way, a character's hit point total is divided in half. Monsters, however don't apply to this rule, unless they're hominids.
One side of this division represents a character's ability (in a combination of the facets mentioned last post) to completely avoid damage in combat. Any damage suffered to this value will completely generate post-encounter after five minutes rest.
The second part of hit points represent the character slowing and tiring as they once again avoid any meaningful injury, with the worst damage being light nicks, glances, and blows completely deflecting off or dragging along armour without harm. Despite this, the character is still not surviving injury with this other set of hit points in the standard sense, but is only fatigued enough to take minor superficial damage that at worse makes a conversation starter. The catch with this second value however, also as a way to balance the automatic regeneration of the first number, is that it regenerates like hit points traditionally do, based on the system being played. Which gives magical healing spells and potions the illusion of being more potent.
On the subject of critical hits and massive damage, my system turns away from hit points, as they do not represent physical damage threshold for characters. Instead, a critical is a roll on the critical chart, with the potential of maximum attack/weapon damage directly to a character's Constitution score, which is indeed threatening. Similarly, falling damage is dealt as 1d4 damage to Constitution per 10 feet, with a 2d10 roll against current CON or get knocked unconscious afterward.