Sudoku Gridmaster uses intuitive Touch Screen controls that make solving the puzzles faster and easier. Simply touch the square you want to fill in, then touch your answer on the number pad. You can also choose to forgo the number pad and write your answer directly on the Touch Screen. Sudoku Gridmaster has plenty of helpful gameplay features to help you solve even the most complicated puzzles. Beginners will love the four in-depth tutorials that can be accessed at any time--even in the middle of a game. Experts will appreciate the ability to highlight entire rows and columns with a single touch. And everyone will wonder how they survived without the ability to highlight all instances of the same number at once. The game features puzzles in four difficulty settings (practice, easy, normal, and hard), and also has a fun unlockable system where you earn stars by performing well. If you gain enough stars, you'll be able to take a test and prove your skills. Pass the test to win a special award and open up even more puzzles.