Sudoku X+

This Sudoku game is intended for the advanced player. Additional features are provided to allow you to solve even the toughest puzzles including: 
1. input error prevention*
2. highlighting*
3. possible numbers* 
4. continuous updating of possible numbers*
5. snapshot screen storage
6. completed numbers 
7. hints 
8. puzzle solution
* configurable options 
You may enter your own puzzle manually or puzzles can be generated internally at one of four difficulty levels. A diagonal puzzle format is also supported. 
This version is intended for the iPhone only and is fixed in portrait mode.