Done in the faux documentary style made famous by "The Blair Witch Project," "Trollhunter" is about several students following who they first think is a bear poacher. In actual fact, turns out he's a real live troll hunter. He's tired of his job, and so he allows the students to follow so that maybe they can blow the lid off the whole troll conspiracy. See, the government doesn't want people to realize there are trolls.
It's a well realized and fun film. The students have all the character of a stick with a painted face, but Trollhunter Hans more than makes up for it. He's gruff and burnt out, but you can tell he sort of likes trolls. They fascinate him. He obviously wishes there was a better way of dealing with trolls than flash frying them with UV lights. The trolls themselves are both well realized and well executed. They never wear out their welcome.
One thing that interests me is this. In the movie the trolls hate christians. If they smell a christian they go berserk. So our Trollhunter tries to make sure that none of the students are christians. Now here's my problem. Let's say I'm an athiest. I find an animal that is capable of smelling the difference between a person who's a christian and one who is not. I'd have to ask myself what makes the difference? That might challenge my athiesm which in this case might make me an instant martyr of troll food. An interesting problem, no?