Four in a Row
Drop a disc and line up four. Two players on one phone, or one against a computer that thinks about it.
Tap a column and your disc falls to the lowest free space. Four in a line — across, down or diagonally — takes the round, and a board that fills with no line in it is a draw. The winning run is struck through, and a move that closes two runs at once gets a line through each.
Play the person sitting next to you, or hand one side to the computer at Easy, Medium or Hard. None of the three plays perfectly, and that is the design: Connect Four is a first-player win with perfect play, so an opponent that searches as far as it can and never errs is not a hard game, it is an unwinnable one whenever it happens to open.
Four boards. Quick is 6 × 5, Classic is 7 × 6, Wide is 9 × 6, and Marathon is 7 × 7, where it takes five in a row rather than four.
Both players set their own name and disc colour, and either can recolour the board. Take the colour the other player is holding and the two of you trade rather than being told no. The whole page washes toward whoever is to move, so whose turn it is is something you see rather than something you read.
The hint aims rather than plays, undo takes back the last move, and the score, the colours and the round in progress are all still there when you come back. Discs land on a note rather than a knock — every cue is synthesised as it plays, and there is not one audio file in the app.
No ads, nothing to buy, and no account. The app has no internet permission at all, so it works with the phone in flight mode and nothing you do in it leaves the device.