Biohazard: Undead Nightmare is a mod, the main mechanic of which is the "real" death of the enemy, only if you shoot him in the head(or he burns, or the damage exceeds GibHealth), otherwise he will regenerate. The mod is made on the theme of zombie apocalypse and on some maps can be similar to Left 4 Dead or Resident Evil (+ if you set the appropriate settings for the atmosphere of level change), for single-player mod is quite difficult, and immediately shows you that to survive alone in the apo