Othello Five

No download, no account: Othello Five is a Hypercasual game that runs where you found it. It is built for touch, so a phone or a tablet is the natural place for it. Catalogued as 1 player, 2 player, 2d, board, casual.

It is drawn for a tall screen, so it fills a phone held upright rather than a wide monitor. Everything runs client-side, so there is nothing to set up before you start.