Descriptions of constraints now added. Click on any text on Check Options screen (press '?').

@Kostya20052011, it is not a game. It is an application for a specific type of puzzle and some of its variants. You use it to either create puzzles for others to solve or you take a known puzzle, plug it in and try and solve it. The application can check your solution for normal sudoku as well as for many of its variants. I will eventually give descriptions of the variants and any object used by a variant. Again, it is NOT a game that you play. It is an application for puzzle solving and creating. Actual puzzles are not anything provided with this application (just like filled in tables are not provided with Excel or QuatroPro).

Sorry everyone. The background is supposed to be quite faint (like in the greenfoot application). Unfortunately, it becomes quite sharp on the site. I will be working on it.