What it is

Battleship, played alone, on squared notebook paper. A fleet is hidden under the grid. Tap a cell to aim and tap again to fire: a blue dot is a miss, a red cross is a hit. Ships lie in straight lines and never touch, so every sunk ship clears the cells around it.

Each page has a shot budget and a target. Hits in a row pay more, a sunk ship earns ink, and the shots you do not use pay at the end. The grid and the fleet grow page by page, and the target grows faster, so by the middle of a run you need what the margin sells: sonar that counts ship cells, mines, bigger shells, spy notes and things you keep for the whole run.