+use it. If you step on a mine, the program will only reveal the mine
+in question (unlike most other implementations, which reveal all of
+them). You can then Undo your fatal move and continue playing if you
+like. The program will track the number of times you died (and Undo
+will not reduce that counter), so when you get to the end of the
+game you know whether or not you did it without making any errors.
+
+(If you really want to know the full layout of the grid, which other
+implementations will show you after you die, you can always use the
+Solve menu option.)