Waterline: Night Plumber

A city sleeps through the rain. Somewhere under the streets, one person keeps the water where it belongs — and tonight, that's you.

Waterline is a quiet, exacting water-equalization puzzle. Every level is a row of tanks joined by breakable walls. Tap a wall, and the water on both sides finds its own level — the volume-weighted average, settled by gravity, every time, exactly. Your job is to break the right walls in the right order until every gold line in the room is met.

That's the whole rule. There is nothing else to learn and nothing hidden: the full state of every tank is visible before you touch anything, and the same taps in the same order always produce the same water. No luck, ever — only reframing what's in front of you.

It starts simple. It does not stay simple. Waterline is proudly, deliberately hard, and it gets harder in every district you enter — the curve only ever rises, checked level by level with an exhaustive solver so no district goes soft. Seventy junctions across seven districts: the Cisterns, where you learn to let water go through a drain; the Canals, where wide basins spill on purpose over a rim; the Metro Tunnels, where a broken wall sends water somewhere else entirely through routed pipe; the Harbor Locks, where a valve only opens one way; the Deep Mains, the old works, the master exam; the Clockworks, where the room's own automation opens gates for you; and the Sealed Gardens, where trapped air is a promise, not a fault. Each new idea is taught by a level built to be solvable only once you've found it — never by a word of instruction.

There is no timer anywhere. Undo is free, instant, and unlimited, because thinking shouldn't cost you a life. Every win shows you your own solution played back, not the game's. Three stars and a par mark reward the clean line, quietly, without ever scolding the messy one.

What Waterline doesn't have: no ads, no subscriptions, no consumables, no account, no always-online requirement, no analytics, no timers, no lives. Levels one through twenty are free, forever; one purchase — never a subscription — unlocks every district after that, including every district still to come. It runs entirely on your phone, fully offline, from the first tap to the last.

The night ends the way every night shift ends — quietly, and without applause. First Light is the seventieth junction and the only story event this game has. The city wakes up. It never knows you were there. That's the point.