Yeah, I have played Sudoku as well. A pity I'm pretty terrible at it. Even the easiest one took like an hour for me to beat and I still got some stuff wrong! I wished there was sound or music. There didn't seem to be anything that different about it. I guess it does make it easier for the game.
I'm just better off playing the real thing. I think it's still a pretty original concept for this website. I usually find Mahjong games more. The colors were nice at least. I can see why this didn't really catch on.