Trine 2 basically improved upon a lot of aspects that Trine 1 kinda faulted on.
You aren't as capable of breezing through a level as easily with 1 of the characters as you could in Trine 1. Which makes the overall need to think a bit more of a priority, instead of grapple this, or magic box that.
Graphics, while don't make the game, are indeed improved upon. I noticed the textures and lighting were improved. Along with this, the backgrounds are just gorgeous, and water is nicer looking.
Gameplay is more tight, since as I said before, 1 character isn't generally viable to clear all the puzzles and enemies. I had to rely on the mage and the warrior alot more in this game, since the puzzles required finesse from both of them. I did not that there were puzzles that clearly were crafted with co-op in mind. Mana was removed, which makes the worry on running out less of a fear. There are some abilities each can use that drains a bar, but it recharges over time.
Along with mana, items were also removed. I'm still 50/50 on this choice, though I think I know why they did it. They want the player to focus more on the puzzles, and less on optimization per character. You can still gain abilities though the skill tree. Which was changed so when you level up; you gain 1 skill point to be spent on one of the character trees; not all of them get a point.
Story I felt is a bit more tangible, I understood the gist of Trine 1's; though I didn't feel like it was really all there. It's easily felt more this time around through collectibles and cutscenes.
Downsides I felt were that the story was a tad too short,I think 1 or 2 more levels probably would have made it ideal, increasing my playtime by an hour or two. Ending battle wasn't completely satisfying.And I wish there was, once again, more variance in the enemies you fight.
All in all though I loved the game. Platforming in general was much better, as were the puzzles. They took general ideals for the puzzles and crafted them in ways that worked great. Initially I thought they'd be rather easy to figure out, later on in the game I find this one concept that was easier in the start; and gradually got harder until it'd make you stop and think. Scenery along the way was nice with well made level environments. And the option of co-op must have made many people happy!
I'm giving this game 5 stars. I think 4 1/2 would be better, seeing as how I can't do that and 4 would say less of the game then I feel it deserves; 5 is the way to go.