Don't know how buggy the windows version is. I got it for Linux (from http://trine-thegame.com/site/index.php) and it runs without any bugs. It's a nice game too. Not mindbogglingly awesome, but still a good, not too hard jump-n-run. It will probably entertain you for quite some hours.

The Whispered World demo should have warned me away from the game, and did for a while. But like a moron I assumed that since Deponia demo ran fine on my system, they would have fixed the cutscene problems in TWW as well. They did not. So now I gotta search youtube wallkthroughs/lets plays for the cutscenes I am having to skip while playing.