We also provided multiplayer mode which you can compete with all the sudoku gamer on line. 【 Features 】 ⊲ Support !!!!!! GAME CENTER !!!!!!!, and Multiplayer. ⊲ Five levels of difficulty for different kind of Sudoku type: Classic, X, Super, Jigsaw and Samurai. ⊲ Load/Save puzzle from/to the application database. ⊲ Statistic, it saves every finished puzzles automatically, that allows you to keep tracking your best played records for each level, you can restart it whenever you want to re-challenge it. ⊲ Pause/Resume which allows you are able to take a short break from the puzzle. ⊲ Undo/Redo the selected number. ⊲ Smart note, automatically put the related note on the field, or put all notes for all fields or clear them all with only one tap. ⊲ Auto/manual check for incorrect numbers. ⊲ Smart eraser to let you remove number on the field clearly and easily. ⊲ Hint, to provide you a easy way to find out current single note field, certainly a little penalty is required :-). ⊲ Keep device from sleeping, your iPhone/iPod no longer sleep while you are thinking in a puzzle. ⊲ Smart coloring fields, allows you to see the relation of each fields while tapping on it. ⊲ In game progress indicator, to show you current progress with a bar interface. ⊲ Compatible with iOS5.0 iPod, iPhone device, Retina Display for iPhone 4/4S/5/6/7/Plus support. Any reviews and ratings are all appreciated, your comments are making this sudoku app become better!!