Minesweeper.

How to play

Reveal every square that hides no mine. A number tells you how many mines touch that square, diagonals included.

Flag a square you are sure about with a right-click, a long press, or F. When a number has all its flags around it, click the number to clear its neighbours.

Press ? for keyboard shortcuts. The rules run on our own C code, compiled to WebAssembly; the same module powers the browser and the command line. Matching the original program is a separate job, and it is tracked in the open.