I really liked it ! Didn't seem to have any problems on my machine, except that it was perhaps a little unresponsive or something ? I'm not too sure, the pieces seemed to lag behind the mouse cursor a little or something. To be fair though, that was the only gripe i could find with it. I also really like the fact that theres a cut down applet version of it on the site to try while you're waiting for it to download.
I should probably reply with the following in the business forum, But i've already replied to you there and I think you'll probaly get more commentary here so here you go.
Its a Jigsaw app, not a game. Now its a GOOD jigsaw app, indeed I don't think i've ever actually seen another jigsaw app . But this could be your downfall when you try and market it, particularly if you're trying to sell it to the portals. I think you should try and actually sell the fact that its a jigsaw program. The selling point is that people can MAKE JIGSAWS from their OWN PHOTOGRAPHS ! So, bit of a roundtable brainstorm here .....
1. People can print out their own jigsaw ? but then they'd have to laminate them onto thick card or wood or something. Maybe not the best idea.
2. Hmmm, partner up with a Jigsaw Manufacturer that makes custom jigsaws for people (I'm pretty sure they probably exist) , so that people can actually order a jigsaw FROM THE GAME and have it delivered or send it off to a friend or whatever.
3. Code up something whereby people can actually save a jigsaw they've created into a redistributable package which they can then send off to friends. Exactly the same functionality as the full version except that it will only display the one jigsaw image.
4. Allow people to upload jigsaws to your site and provide a URL so they can send this URL off to others to mess around with their jigsaw, you already have a perfectly fine applet in place to do just this.
Obviously all this functionality is only available to registered users :-)
D.
As far as the lag when picking pieces goes - well that just calls for some more optimisations from my part. I did work on optimisations, but there's always more to be done

.
Also thanks for your ideeas - some of them I've thought of before, some are fresh. The thing is that now I'm kinda exhausted and I feel the need for some rewarding of my efforts - be it visitor count, download count or paychecks

. So if it gains some popularity, I'll feel encouraged to go on adding features.
Thanks for the positive feedback - it really helped. (spiritually if anything else).