Experience points
A numeric currency awarded for defeating enemies, completing quests, and performing activities, accumulating toward level-ups. XP is gaming's most universal feedback loop: it converts every action into visible progress, guaranteeing that time invested always produces growth even when a session's goals fail. Designers use it to pace content (level gates), to steer behavior (whatever grants XP is what players will do — the XP-per-action table defines the game's real values more honestly than its story does), and to let grinding work as a player-controlled difficulty knob. Key decisions: kill XP versus objective XP (kill XP rewards clearing everything; objective XP permits stealth and pacifist builds), party-split rules, rubber-banding (reduced XP from low-level content prevents degenerate farming), and rest bonuses. Pitfall: rewarding XP for the wrong verbs — if talking grants less than killing, the diplomatic build is a second-class citizen no matter what the narrative claims.
- Dev effort: Small
- Timing: Real-time or turn-based
- Common in: rpg