I really only just barely started Trine, so I'll try not to pass too much judgement on it, particularly since I think I'll be getting back to it, but I thought I'd capture my initial impressions.
Gameplay is sort of a Lost Vikings style of gameplay (or I guess people are now saying "Trine" style - was that because of this game, or is that what it's actually called?). You have 3 characters that you can switch between by hitting numbers 1-3. The Wizard can create blocks when you draw a square with the left mouse button, and lift and move things around with the right mouse button. The thief can shoot arrows with LMB, and use a grappling hook with RMB. Finally, the warrior can hit things with his sword with LMB and use his shield to protect himself with RMB. You can switch between them at any time. All 3 have individual health bars, but I haven't seen any huge fallout from someone dying - they seem to just come right back after a few minutes of using a different character.
Basically, you are progressing your characters from the left side of the screen to the right side. You are met with several challenges and puzzles in terms of figuring out how to use your characters to open doors, or finding the right way to progress forward.
What I Liked:
Core Concept. I really think this style of gameplay is neat - using multiple characters that have exclusive abilities. We tried to do something like this for one of our week long game jams - but really figuring out a concept like this is hard!
Start. The opening of the game was very engaging. Each character go this or her own 5min section of gameplay, leading up to where they were all joined together by the Trine. It's the perfect amount of time to get a good sense of what each character can do, and the narration & voice overs give you a great sense of the characters' personalities, which are very fun.
Narration. The narration is engaging and fun, and does a lot to set a light-hearted mood. This game could have gone several directions in terms of mood - but the narration keeps it on the fun side as opposed to being a game that takes itself too seriously. (Which maybe makes you a little more forgiving of things like really high jump heights, or places where the physics don't behave completely as you'd expect.)
Visuals. Overall, it's a very pretty game! I am interested in seeing more of the world, in addition to facing puzzles and challenges.
What I Didn't Like:
Small physics issues. Again, I didn't play enough to pass too much judgement. I did notice some very small physics issues - as in, places where physics didn't behave exactly as I would expect. That being said, it wasn't so bad that I felt frustrated or wanted to stop playing.
How Do I Feel About Continuing?:
I definitely want to keep playing. It's a cool game concept and I want to see more of where they went with it! I should probably pick up Trine 2 also. :)