Flow Free

Flow Free is what happens when a puzzle game refuses to add anything. There is a grid, there are pairs of coloured dots, and you draw a pipe between each pair without crossing any other pipe. Every square must be filled. That is the entire game and it has not needed a single feature since 2012.

How it plays

Each level is a small square grid — five by five to begin, considerably larger later — with pairs of coloured dots scattered on it. Drag from one dot to its twin to lay a pipe. Pipes cannot cross, and a level is only solved when every square on the board is covered. That last condition is what makes it a puzzle rather than a maze: joining the dots is easy, joining them so that nothing is left empty is the actual problem.

What's great

It is completely untimed, works offline, and holds its position if you put the phone down mid-level. The difficulty curve is unusually well judged — grids grow one row at a time, so you are never hit with a jump. There are thousands of levels in the free version alone, which for a puzzle this compact is close to absurd value. And it is legible at a glance: no tutorial, no currency, no meta-progression to keep track of.

What holds it back

It is repetitive by design, and there is no getting around that. The visual presentation is functional at best — flat colours on a black grid — and the free version carries a banner ad that sits awkwardly close to the play area on smaller phones. There is also no sense of progress beyond a level counter, so it gives you nothing to come back for except the puzzles themselves.