I've had this game for less than 24 hours and I'm already intrigued. Like the another reviewer said, it does exactly what it sets out to do. It's both challenging and fulfilling (especially upon completetion of a puzzle). I love this game, and I don't think I can ever look at Sudoku in the same way again.I also agree that there should be a brief introductory thing, if anything, although I don't think anybody brand new to Sudoku would even attempt this. The interface could use improvement, though its simplicity prevents distraction. Great to keep anybody busy for a long time.

This game does exactly what it set out to be. The easy version can be incredibly easy, while the harder versions can be insanely hard. If you are looking for something to keep you occupied for a really long time, this could be the thing for you. The only thing that could make this cooler, would be a little bit "apple(er)" interface. Also a hint system, or how-to, or some way to learn how to play sudoku in this style.