Adam's Lab.

Reveal every square without a mine. A number counts mines in the eight neighboring squares. Click to reveal; right-click or switch Flag mode on to flag. Your first click and its neighbors are always safe.

Click a revealed number when its neighboring flag count matches to reveal its other neighbors. Incorrect flags can make this chord hit a mine. Use arrow keys to move, Enter or Space to reveal, and F to flag. On touch, use Flag mode. Select a difficulty or the face button for a new game.