GrandGames Sudoku (Windoku, X,

You can solve not only classic sudoku puzzles, but also sudoku variants such as Diagonal Sudoku, Windoku and Killer Sudoku. Application contains 640 the most interesting offline levels. Tens of thousands of other levels are available in the online catalog for free. The application has both very easy levels, suitable for beginners, and extremely difficult, suitable for experts. New sudoku puzzles are added daily!