It will be more fun. ◎ There are few difficulty levels you can select ◎ You can use hints during playing, if necessary. ◎ Have note function. It's useful. ◎ Game Center supported. There have few leaderboards and chievements for you to challenge. ◎ User friendly color style, which can help you to find the correct answers. ◎ Build in few thousands of questions database. Even you have become a Sudoku king, please challenge again and you will get different questions.