Mechanics

NetHack monsters have alignment (chaotic, neutral, lawful). Killing monsters of opposing alignment shifts player alignment. Corpses can be sacrificed on altars to gain favor with the player's god. Alignment affects which artifacts can be used and divine intervention.

NetHack allows players to genocide monster species via scrolls of genocide, permanently removing them from generation. Monsters have geno_flags (G_GENO, G_NOGEN, G_UNIQ) controlling eligibility. Genociding unique monsters is dangerous. This creates a strategic resource management tension.

NetHack items (potions, scrolls, rings, wands, spellbooks) are generated with randomized appearances. Players must identify items through use, scrolls of identify, or price identification. Wrong identification can be lethal (drinking poisoned potions, reading cursed scrolls).