My daughter loves this game, and after using the trial version for a while I decided I'd buy it for her. The purchase was easy, but as the trial version had expired it was asking for the registration number. I tried to enter the serial number once it had been emailed to me, but kept getting an error that it was invalid.
I tried deleting all the prefs and reinstalling, but couldn't clear this error. I emailed support and after a week have not had a reply. In the end I fixed it by installing it from fresh on my own Mac, and then copying all the supporting files to my daughter's Mac.
Despite that, I feel the game was a worthwhile purchase, as it seems to have kept my daughter quite well occupied.