"Do you consider yourself an expert at solving sudoku? Challenge yourself here in Samurai, Triples and Heart modes."
If you consider yourself to be an expert at solving sudokus and are bored of the classic games because they are too simple, then you should take a look at this program called Sudoku Sensei 2.0. As the name indicates, Sudoku Sensei 2.0 is a fully integrated sudoku engine, ie a program that can solve sudokus just like we do.
In Sudoku Sensei 2.0 you can design the boards yourself, then have fun trying to complete them. You can assign levels of difficulty and also levels of help. There are five levels, which get progressively harder, and there are five games in each level. You can also activate or deactivate the hints and tips, depending on how confident you feel in your ability to complete these tricky 3 x 3 boards where no number can be repeated. However, if you are a novice then there is a tutorial and demo video of how the Sudoku Sensei 2.0 program works. This way you can familiarize yourself with the rules and how to go about solving a sudoku if you aren't already familiar.
Sudoku Sensei 2.0 comes with a full explanation of the game system, an Introduction section to explain everything about the program, and also a Glossary of terms. There is a way to report any bugs you find too.