How we tuned 185 levels of Swap
Puzzle games live or die on difficulty. Too easy and players get bored; too hard and they quit. When we built the 185 levels of the Swap Journey, we didn't want to set difficulty by feel alone, so we built a model of how a casual player and a skilled player would do on every level, and tuned against it.
What makes a Swap board hard
Three things matter most:
- How many tiles are out of place. More wrong tiles means more swaps and more chances to slip.
- How subtle the colors are. A board whose neighbours differ by a sliver is far harder than one with clear steps, even with the same number of wrong tiles.
- How many spare swaps you get. Every level allows a few mistakes. On early levels that cushion is generous; on bosses it is small.
Shapes and mechanics add to that: rings you have to follow all the way round, hearts and diamonds with narrow points, and frozen tiles that can't move until you fix the tiles around them.
The rhythm of a world
Each world follows a pattern rather than climbing in a straight line: a couple of easy levels, a medium one, a Hard level, then a relief level to breathe, and so on, ending in a Boss. A steady climb wears players out; peaks and valleys keep a world fun all the way to the boss.
The numbers
For every level, our model estimates the chance a casual player wins on the first try, how many tries it takes on average, and how much a rescue helps. We aim for roughly the pacing hit puzzle games use: easy levels around 90% first-try, medium around 75%, Hard around 45% and bosses around 20%.
Here is how the first world, Warm Up, came out for a casual player:
- Level 1 (easy): 2 tiles out of place, 1 swap needed, about 100% win on the first try.
- Level 4 (the first Hard): 6 tiles, 3 swaps, about 92%. Still gentle, on purpose.
- Level 9 (Hard): 11 tiles, 6 swaps, about 60%.
- Level 15 (the Boss): 18 tiles, 10 swaps, about 28% on the first try and around 3.6 tries on average. With one rescue, about 64% win.
Across the whole Journey, the average first-try win for a casual player sits between about 73% and 86% per world, and the bosses get steadily tougher: from about 28% in World 1 to about 16% in World 9, Deep Freeze.
What happens next
A model is only a starting point. As more people play, real results will show where it was wrong: a level that is much harder than it should be, or a boss nobody struggles with. We'll keep tuning, and the changes will show up in What's new.