15'000 puzzles, eight difficulty levels, the world's best hint functionality and statistics. The only Sudoku app you'll ever need! Game Play. Eight different Sudoku variants: Classic & Jigsaw puzzles Asterisk-, Centerdot-, Color-, Hyper-, Percent- & X-Sudokus. Eight difficulty levels: very easy, easy, moderate, advanced, hard, very hard, fiendish, nightmare.