Very well done, though a bit lacking.
Nice work on this project!
I (also) recently discovered Sudoku. I've been playing a flash version of it on another website for a few weeks now and really enjoy it. You interpretation is nicely done, although there is definitely room for improvement.
Suko, I am unfamiliar with. I like it, but I prefer Sudoku for the challenge.
I noticed a few odd bugs in my travels. Note that I am using FlashPlayer 7 because 8 apparently does NOT want to work in Firefox 1.06. Sigh. Any how, the timer seems to count by thousands, thus making getting on the high score list nigh-impossible.
Also, I found that once a puzzle was completed, when you play again, it start with the empty completed puzzle and you have to click "new" to play a new one. That may not be a bug, but it was a bit odd.
Overall, this is quite well done. I don't see any real need to add sound effects. It's a brain puzzle, so sounds are not really needed (the other version I play I turn the sounds off anyhow). I would like to see a way to temporarily mark a space to help solve the spaces. Perhaps a "pencil" option or something like that. Otherwise it ends up requiring a lot of memorization.