The Classic Sudoku, as well as more than 70 innovative configurations: Different types: Classic, Diagonal, Hyper, More-or-Less Sudoku. Different shapes: Single, Double, Triple, Zigzag and Samurai Sudoku. Different sizes: 4x4, 6x6, 9x9, 12x12 and 16x16. Multiple difficulty levels: for beginners, and for the master-class players.