Your goal is to activate all squares without a mine under.
Drag the slider to change the density of the mines. Click Save to start a new game with the density selected.
Definition surrounding squares:
the squares that are (diagonally) adjacent to the current square;
a square usually has eight surrounding squares, if in the middle of board.
Definition flag:
a symbol on a square that a player places to mark that there is a mine under the square.
Left Click:
Unactivated square: Activates the square.
If there's a mine under, game over; if not, shows the number of mines surrounding it
Revealed square: Tries to activate the surrounding squares without flag.
If number of flags surrounding the square equal to the number on the square, then activates surroundings successfully.
If not, it will just light up the surrounding unactivated squares.