I have published this update to try to solve some confusion.

In previous versions of the game, an incorrectly-placed flag has been represented like this:
Note the image of the mine with an X above it. This is how incorrectly-placed flags have been represented in other Minesweeper games too.

It seems that this representation has caused some confusion.
Several players have left negative reviews, and seem to think that the mines have been miscalculated or the game is bugged.
I can't find any evidence of such bugs in my own testing, and most players have left positive reviews with no mention of any bugs.
I have concluded that this incorrect-flag sprite is the cause of the confusion.

To try to make this clearer, I have replaced the 'mine-and-X' sprite with just the 'X' sprite.
See this image:
This should make it clearer that there is not actually a mine here, but that the player placed their flag on an incorrect square.

Please let me know if this update makes the game easier (or harder) to understand.
Minesweeper Ultimate now has over 8000 players, and I want everyone to enjoy it.
Of course, I'm still open to the possibility that there is actually a bug somewhere that people are experiencing.
Please tell me if these changes improve the game for you!