tl;dr — daylight is a resource. Spend it wisely or the dark spends you.
The problem
A flat difficulty curve made survival predictable. We wanted dread that builds as the clock ticks.
What we did
A dynamic day/night cycle drives everything: by day you scavenge, craft and prepare; at sunset mutants emerge, get faster and smarter, and unpredictable events kick in.
The result
Players self-impose tension — "one more house" becomes a real gamble. Returning before nightfall is the core decision of every run.
Next
Weather layered on top of the cycle: storms that mask sound and cut visibility.