Click a square. If it shows a number, that is the number of mines touching it. If it shows a mine, it has exploded and the game is over. The objective is to use logic to uncover all safe squares leaving only the mines covered.
Unlike most Minesweeper games, this one attempts to generate every board with a consistent difficulty level. In each board, 99 mines are scattered in such a way that the board has an optimal solution of exactly 174 clicks (i.e. 174 3BV) meaning that highscores can be fairly compared timewise (very lucky boards cannot occur).
As an alternative to overusing your clicking finger (which may cause Carpal Tunnel Syndrome), you may instead use the spacebar (or any other key) to select a square. The ESC key is one exception which is reserved to abort the current game.
External linksAuthoritative Minesweeper