Zig-Zag Pressure

Your ball travels diagonally and the button flips it vertically — that is the whole input. Walls slide in from both sides and squeeze the room between them, and every wall you bounce off scores, with a multiplier that climbs each time.

That multiplier decays on its own, once a second, which turns the safe play into the losing play. You have two lives and an extend, so the run rewards going back into the gap you just escaped.

From Kenta Cho’s MIT-licensed crisp-game-lib collection.