Tumbleworks

You are a ball of clay rolling downhill through a handmade workshop, and the rule is one sentence: anything you roll over sticks to you, and everything stuck to you makes you bigger.

Mass is the only stat. It starts at 1.00 and each absorbed object adds 0.05 to 0.60 of it. Bigger is stronger — past mass 2 you go through matchsticks and corks, past 4 through books and tins, past 7 through the workbench leg itself — and anything above your tier is a wall you bounce off. Bigger is also wider, and three gates stand across every course. The third is always the tightest, so a run that ate everything arrives at the last one too fat to pass. Smashing an obstacle leaves 15% of your clay on the floor behind you, which makes destruction the only way to get smaller. That is the argument the whole game is about.

How it plays

• Four courses of downhill bench, generated from one fixed seed so every player rolls the same four — course 1 is 239 m — with gates at 25%, 55% and 85% of the length. A course runs 46 to 78 seconds, so a full sitting is about four to five minutes.
• Steering authority falls as you grow: 5.0 m/s of lateral travel at mass 1, down to roughly 1.3 m/s at mass 12, on a track 3 to 6 m wide. The clumsiness is the cost of the power.
• On the approach to a gate the readout draws your circle inside the gate's at one shared scale, so you can see whether you fit before you commit. When you don't, it names the exact mass to lose — and each smash takes 15%.
• Every course is proved before you see it: a greedy absorber that takes everything and an avoider that takes nothing must both reach the end, and a seed that fails either is thrown away and rolled again. Over a 50-seed sweep every course passed, at 1.73 attempts each.
• No death — you can only be slow. Falling off returns you to the last checkpoint with your mass intact and the obstacles re-formed, so a bad line costs time and nothing else.
• The 24 most recent objects stay jabbed into the clay at the angle they hit; older ones merge into the silhouette as bulges. The ball ends up a record of the run.

Greed is not the shortcut it looks like. Across the four courses a mixed line scores 14062, 15726, 12202 and 12934 against a pure absorber's 11884, 16074, 11803 and 11789 — three courses to the mixed line, and the second to greed by 1.8%.

Plasticine and paper: matte clay under one soft light on a paper sweep, with the ball quantised to 12 frames a second while the rest of the world runs at 60. That stutter is the stop-motion look, and the pause menu turns it off if it reads wrong to you.