We just released update #5! We added three more example levels to the level editor and one concept level to the game's main menu, so check them out! I also recommend playing through the existing levels again, since you might run into something... or someone new. ;) Other updates include multiple fixes and improvements to both the editor and levels, so hopefully they should also run smoother now.
Check out the Steam Community Discussions for the full changelog. :)
Oh, and remember to check out this blog post for a chance to get dialogue written by yourself voice-acted by the actual Trine Heroes to be used in custom levels. :)