Peak-End Rule

A cognitive bias where people judge an experience primarily by its most intense moment (peak) and how it ended, not by the overall average experience.

In games, this means

Players remember the thrilling final boss and the satisfying ending credit sequence, not the three frustrating hours in the middle. Designing a spectacular peak moment and a rewarding session end-state matters more than optimising every moment equally. The worst thing a game can do is end on a crash, a confusing transition, or a failed save.