I don't know, man. They never explained the 'powers' or the trolls. The parents keep them locked up, never to even talk? The queen runs away and wants to become a hermit in an ice castle?
Although predictable, the prince turning into the bad guy was a twist, but his plot to take over was developed awfully quick in his head. He friended her, fell in 'love', and then decided when she left to try and take over?
I know its a kids movie, but this one seemed like it was thrown together without much effort.
ETA: Sorry, edited title for spoilers after I posted this
This post was edited on 1/2 at 1:20 pm