Actually I'm more interested in the game board. If a space has (say) 3 mines next to it, then the numeral 3 will appear (as today). However, when I add a flag next to it, then the count should go down to 2 -- i.e. the number is always the number of mines minus the number of flags. It takes a bit of getting used to when first using that mode, but it becomes much quicker after a while as there is no more checking that a cell with a '4' has 4 flags around it, so all the other adjacent cells are safe. The countdown rule means that a cell with 0 in it, all the open adjacent cells are safe (assuming that the flags are in the right place!!).