Designing For The Peak-End Rule

Among the many biases humans suffer from is the peak-end rule. When remembering an experience, you overweigh the most intense part (the peak) and the last part (the end). In game design, what makes a great peak and what makes a great end are not always the same. A great peak lets players do something spectacular that makes them feel clever or skilled. A great ending brings closure to the game's events in a satisfying way. You want to make sure your game has both.

Games with mysteries that end with a big reveal do this easily because the exciting moment also provides closure. Blood on the Clocktower often ends with three demon suspects left. Because of the ghost vote mechanic, many of the dead players vote in the final round, adding to the spectacle. After they vote and learn who won, the GM explains what occurred during the game. The post-game explanation is engaging and lets players recontextualize the entire game. By combining the peak and the end, Blood on the Clocktower creates positive memories.

Even outside of social deduction games, many games end with a reveal in the form of scoring. In 7 Wonders, you tally up your points at the end of the game on a scorepad. This brings closure by showing you how well you did. However, it is harder to create a peak here because the actions that led to your score happened much earlier. During the game, there are other peak moments like military victories or playing expensive cards for free using links.

Scoring at the end of the game has a drawback: big moments during the game can feel smaller if they don't result in a score immediately. Fortunately, you don't need to do all your scoring at the end of the game; having only some points hidden can work too. In my game Sprocketforge, players earn most of their points publicly, but also get secret "favor" cards worth points at the end. This creates an exciting reveal at the end of the game while still allowing for huge turns throughout.

If you can't guarantee that the peak comes at the end of the game, you can at least make sure it is spectacular. Some say Spirit Island ends anticlimactically, but during play it is good at creating opportunities for amazing turns. Some major powers do ridiculous things like:

• Spamming minor powers for free (Transformative Sacrifice),
• Teleporting a Dahan army across large distances (Wrap in Wings of Sunlight)
• Permanently removing an entire board from the game (Cast Down Into the Briny Deep)

Letting players pull off crazy things is especially important in attrition-based wargames. Because attrition weakens players over time, an anticlimactic ending is a real risk. Heroscape has many unit abilities with a low probability of a gigantic payoff. For example, Ne-Gok-Sa's Mind Shackle steals control of an enemy unit if you can roll a 20 on a twenty-sided die. It almost never happens, but when it does, it creates an instant peak to the game.

The Bene Gesserit faction in Dune creates one of the craziest moments I have seen anywhere: stealing victory through a prediction. At the start of play, they secretly guess who will win and how many turns the game will last. If correct, they alone win. Because this necessarily occurs at the end of the game, it is doubly powerful as a memorable moment. I still remember the one time I achieved a prediction victory, over a decade later.

Be careful, though: the peak-end rule works for both negative and positive peaks. Having your unit stolen by Mind Shackle or your win stolen by the Bene Gesserit could be a negative peak. It is much easier in cooperative games like Spirit Island because your win is not someone else's loss.

We sometimes avoid letting players do ridiculous things because of concerns about game balance. But memorability matters more than balance. If you want players to have positive, memorable experiences with your game, you can:

• Engineer the peak of the game to occur as close to the end as possible.
• Provide closure at the end of the game in the form of a reveal or scoring special points.
• Allow players to do crazy things occasionally to create very high peaks.