Damage/health mechanics in RPGs

Hit points: Damage either subtracts from or adds to a track of specified capacity; death/incapacitation upon depletion (for subtractive damage) or filling up (for additive damage) of this capacity
  >Eg, D&D, L5R, WoD, ORE, DH
	Vitality/wounds: HP divided into two tracks, one which heals fast
	 >Eg, D&D (variant rule in 3.5), Fantasy Craft

	Death save: Death/incapacitation is not automatic upon depletion of HP; rather, having HP depleted prompts checks to avoid succumbing. Checks may be prompted upon total depletion of HP, each round while at or below 0 HP, and when taking damage while at or below 0 HP.
	  >Eg, D&D (variant rule in 3.5; default in 4e)
	  *May be used in combination with standard HP mechanics (ie, death saves prompted during intervening "dying" state but death may still automatically occur upon reaching a certain further level of damage) -- eg, 4e
	  *May incorporate elements of damage save mechanics (below)

	Wound penalties: Suffer escalating penalties the more damage suffered
	  >Eg, L5R, WoD

	Hit boxes: Rather than simple tracking of a total health or damage integer, each point on the track is a "box" that can be filled with any of two or more kinds of damage, representing varying degrees of severity. Usually, lesser kinds of damage heal more easily and are not capable of killing, though multiple instances of a lesser damage type to the same hit box may escalate to a greater damage type.
	  >Eg, WoD, ORE

	Hit locations: Separate tracks for each limb/body region, with location of hit determined randomly (but usually with some options for "called shot")
	  >Eg, ORE

	Critical damage: Depletion of hit points does not automatically kill/incapacitate, but rather causes further damage to inflict serious injuries. The more critical damage accumulated,
the more serious the effects of each subsequent hit. Death/incapacitation are determined by the specific effects of the injuries suffered.
	  >Eg, DH
	  *May incorporate elements of damage save mechanics (below)



Damage save: Damage adds to a total, and each hit prompts a check with difficulty proportional to the accumulated total. On failure of this check, you suffer some ill effect (a negative condition, injury, incapacitation, death, etc.). Damage total may reset on a failed check, or simply continue escalating until the end of combat, or even until healed by normal healing effects.
  >Eg, D&D (variant rule in 3.5), Fantasy Craft, Legends of the Wulin

	Hit tracking: Rather than a damage total, you track only the number of hits taken. The check difficulty is determined by the damage of the individual attack, and your accumulated number of hits taken (so the damage of the present attack is important, but not the damage dealt by past attacks).



Stress/consequences: Each hit fills in a single slot on a track, based on damage value, rolling up to the next higher slot if the specified slot is already filled. A consequence can be taken to mitigate a hit; consequences must be taken if no slot is available to take the hit.
  >Eg, FATE