Health

A player’s health starts at 100%. It is increased by various powerups and can be increased up to 200% in Doom version 1.666 and later(earlier versions allowed health to excede 200%). It is decreased by enemy attack and environmental hazards (damaging floors, exploding barrels, and crushing ceilings). If a player's health ever drops to zero, then that player dies.

The health number is not really a percentage of anything. It can be considered as just a number, or as hit points.

The current health is shown on the status bar, both numerically, in “percent”, and graphically, by the condition of the player’s face.

If a player has armor, then when the player is attacked, the armor will absorb some of the damage (one third or one half, depending on the type of armor) and thus lessen the decrease in health.

Monster Health/Hit Points

 * Zombieman - 20
 * Shotgun Guy - 30
 * SS Nazi - 50
 * Imp - 60
 * Commando - 70
 * Lost Soul / Doomguy - 100
 * Demon / Spectre - 150
 * Revenant - 300
 * Cacodemon / Pain Elemental - 400
 * Arachnotron / Hell Knight - 500
 * Mancubus - 600
 * Archvile - 700
 * Baron of Hell - 1000
 * Spiderdemon - 3000
 * Cyberdemon - 4000

Furthermore, barrels have 20 hit points, and John Romero's head has 250.