Day/night cycle
In-game time advances continuously, cycling lighting, NPC schedules, spawns, and available activities between day and night. The cycle makes a world feel like it exists independently of the player: shops close, guards change shifts, monsters emerge after dark. Designers use it to vary the same space (one map, two moods), to create scheduling gameplay (Stardew Valley's day is a time-budget puzzle; Majora's Mask made the schedule itself the puzzle), and to pace risk (Minecraft's first night teaches the entire game loop in one rotation). Key decisions: cycle length (too short feels strobing, too long means most players never see night), whether time passes during menus and dialogue, player control (beds and wait commands are pressure valves that also deflate urgency), and how deeply NPCs schedule — full routines are enormously expensive, and most games fake it with two states. Pitfall: night so dark it is unplayable — atmosphere losing to usability. A common gameplay hook is visibility: darkness shrinks sight lines and detection ranges, favoring stealth at night and making light sources strategic.
- Dev effort: Medium
- Timing: Real-time
- Common in: open-world, life-sim