A fun mine sweeper game
- tap on a cell to reveal it
- long tap on a cell to flag and un-flag it
- tap on a revealed cell to automatically flag all hidden cells/reveal all hidden cells if it is obvious that the hidden cells are all flags/numbers
- tap "undo" if fail
- tap "new game" if want to start a new game
- choose between "easy", "medium", and "hard" mode for difference grid size and number of mines