I liked the demo very much. The graphics, playstlye and especially the voice acting all added to the atmosphere.
Essentially, its a simple platformer that reminded me very much of prince of persia, the original. Fun play with some puzzle challenges. The mulitple player types is a blast and the up comming co-op mode will be a blast!
Take a looksee and d/l the demo. http://trine-thegame.com/site/
8/10 – makes a change from the FPS/MMPOG stuff I have tinkered with lately.