Sudoku.gs software offers a flash-based Sudoku puzzle with advanced features such as pencil mark. The software also provides a website www.sudoku-ball.com for additional Sudoku options.

In addition to Sudoku.gs, I was also directed to check out Sudoku-Ball, which offered a unique twist on the traditional Sudoku game. Powered by Java3D, Sudoku-Ball challenges players to solve a complex 14 Samurai Sudoku network on a spherical object, requiring players to close the entire network in all directions.
Overall, I found the interface and gameplay of both Sudoku.gs and Sudoku-Ball to be enjoyable and intuitive. The inclusion of pencil marking and other features made for a smooth and stress-free gaming experience. I highly recommend checking out both games, and am excited to continue playing Sudoku.gs and Sudoku-Ball in the future.
Version 1.0 Stable:
Added:
* Load and save your game.
* Game timer and scores
* Pencil marking
* First order error indication