All Star Sudoku

Designed for phones and tablets, All Star Sudoku is feature rich and easy to use thanks to an intuitive user interface with a zero learning curve. New users can install the app and begin using it immediately.
Features Include:
Unlimited undo and redo. Readily accessible Undo and Redo buttons located beneath the grid make it a snap to branch off on an experimental solution path and to effortlessly return, step by step, if the path leads to a dead-end.
Save and Restore Current State. An alternate way to branch off on an experimental solution path and to instantly return if the path leads to a dead-end.
'Unfilled Sudoku' mode. You can work Sudoku puzzles from your favorite printed sources and even use the automatic solver to instantly solve even the most difficult Sudoku puzzles.
Includes Sudoku puzzles for all skill levels. Includes many thousands of single-solution true one star, two star, three star and four star Sudoku puzzles.
Works with or without a data connection. The app is fully functional when in Airplane Mode or whenever a data connection is not available.
Automatically calculates possible candidates. Manually calculating possible candidates is error prone. It also is a time and battery consuming process. All Star Sudoku automates this process to save you time and battery life. This feature can be toggled on and off as desired.
Check and Remove Errors. You may not need this one, but in case you do it is available. If errors are found they will be removed from the Sudoku grid (and your solve time will no longer be valid).
I Give Up! Show Me The Answer. When frustration sets in, the solution is only a click away.
Well-Behaved App. All Star Sudoku is a well-behaved app. It will never hog your resources, auto start or run background tasks.