Runoff: Flow Puzzle

Pour a cell and watch water find its own way downhill, split on ties, and pool in the basins. Wet every green target, dodge every red hazard, inside par + 1 pours.

A pocket-sized watershed.

Pour a cell and water finds its own way — downhill, splitting where two paths tie, spreading flat across a basin floor until it spills over the low side. Wet every green target, never touch a red hazard, and the level is solved — in exactly par pours if you read the terrain right, one more if you needed to feel your way there.

Every pour is a pure function of the terrain underneath it: the same tap always sends water the same way, there's no timer and no luck. Par isn't a guess either — it's the exact minimum a brute-force search found for that board, so a level with par 3 is provably not solvable in 2.

WHAT IT DOES

• 48 levels across four chapters — Trickle, Runnel, Basin, and a fourth that leans on everything the first three taught you. • Real terrain, not a colour code: dark is low, pale is high, and a numeral in every cell gives you the height even in grayscale. • Undo and Reset are free and unlimited. The only thing that costs you is a wasted pour. • A high-contrast palette, an option to hide the height numerals, and a choice between watching the water run stage by stage or resolving it instantly. • Dark mode, Dynamic Type and full VoiceOver — every cell is a button that reads its row, column, height and wetness aloud, and a finished pour announces what it did.

WHO IT'S FOR

Anyone who wants a puzzle with real mechanics under it — not tile-matching with a water skin, but an actual small hydrology model, quick enough for a coffee break and exact enough that the par badge means something.

PRIVACY

Runoff runs entirely on your device. There's no account, no network connection, and no analytics — every level you've solved lives in this device's storage and nowhere else.