A few UI issues I enjoy this game a lot, and now play at the expert level. Two issues about the screen: if the screen doesn't react to the switch to marking mode, then selecting a number for marking becomes a play, and you get an x. Second thing is the numbers are too close and it is too easy to fat finger.
Nice, simple Sudoku game Although it might be considered cheating to Sudoku purists, as a casual player, I really like the way it automatically highlights the selected number in other quadrants, and deletes notes that are no longer relevant.