If you’ve played a game anytime in the last decade, chances are you’ve heard the “ba-boop!” sound that signals the unlocking of an “achievement”: a supplementary goal parallel to a game’s core objectives. Achievements have become an expected part of modern game design, but what can we say about how and why they work? What separates the great achievement structures that keep us striving for 100% from their more forgettable counterparts? Let’s open up the trophy case and see what we can learn about the motivational science and artful design of compelling achievement patterns.