It should be solvable by logic not trial and error
Overall I do like this Sudoku game. Yet, once you get to the difficult level, most of the times it can only be solved by trying out the combination of one or several pairs, e.g. by guessing. Once you get to the point where it it obvious that your guess was incorrect you have to revert to the point where you made the first guess and try again. This I find really annoying. I would much prefer if all levels could be solved by logic alone. For that reason, I rate it 3 stars only. Otherwise, it would have been 5.
