I picked this game up during a Steam sale last year for the Bootcamp partition of my Mac for $5. It was hands down a really good investment. I got an average amount of play time out of the game, potentially around 15 hours or so I think if I remember correctly.
Needless to say I was thrilled when the game ported to Steam for Mac this year as well and this great game can now be shared with the Mac community.
The graphics are beautiful in themselves. You could pretty much just sit there and and watch the area you are in and just see the amount of detail that went into crafting each level.
Some puzzles in the game take a bit of thought and others take a bit of chance/skill/timing to get it nailed.
The storyline was alright, but I wasn't really attached to it by any means. I just wanted to run the levels and see all the eye candy and run the fun and intuitive missions.
From my experience on the Steam forums for this game, they have pretty decent tech support and are really quick to get back to you and will be up front and honest with you when it comes to whatever you experience.
There's a Trine 2 coming out soon as well so you should totally check this one out and prepare yourself for the second!