CONTAINS SPOILERS AND A BIT OF A WHINGE
Can we please ease back on the whole found footage thing? Can film-makers please stop trying to pretend that the patently fictional material is real? When it was a new and innovative technique back in the days of Cannibal Holocaust, or later with The Blair Witch Project and a couple of other early entries, it was a persuasive way of bunking up the realism. But now, with a whole raft of movies doing the increasingly feeble "it was all real, the people were never found, this is the actual footage they shot" routine, it has become less of a tool of verisimilitude and more of a getout for people who don't know anything about lighting, editing, picture composition or the price of tripods. Can't make the film look good? Simply turn it into a pseudo-camcorder job, because they're supposed to look like crap.
You can get away with the fake camcorder routine with stuff that's just about possible or at least believable - Lake Mungo is a chilling and convincing mockdoc than never drops the ball, and The Blair Witch Project did more or less work - but you can't apply it to stuff that we all know has no basis in reality at all. (If I have any quibble with This Is Spinal Tap, it's surely that the real/fake game is over when John Steed walks into shot.) In that respect The Troll Hunter is about as convincing and plausible as the outtakes they run at the end of digimations like Toy Story or Monsters Inc. Because it's about trolls! Yup: trolls are real and a trio of Norwegian college kids on a media studies course shoot 283 hours of camcorder footage (apparently less than two hours are deemed worthy of release, so Odin alone knows what the other 281 hours are like) when they encounter Norway's only official licensed troll hunter and go off on midnight troll-hunting expeditions in the woods with him.
There are large trolls, three-headed trolls, and a ginormous trollzilla thing that can probably be seen from space and yet the film is trying (and failing) to convince us that the Norwegian government is trying to keep their very existence a secret - you might think that pylons are there to carry electricity across the countryside but they're really a giant electric fence; all troll attacks are blamed on wild bears that have walked over from Russia, and the key bit of evidence that trolls exist is that the Norwegian Government have categorically denied it. In the same way that I categorically deny any involvement in the Brinks-Mat bullion robbery or the disappearance of Shergar.
Really, stop doing this. Just make a film. Make a proper film with edits and lighting and scoring, utilise the techniques of cinema that have been developed and refined over more than a century. It's a lame gimmick and it doesn't work for a second. Granted, the special effects are perfectly acceptable, in a Cloverfield style (handheld nightvision wobblicam) and there are a couple of good laughs in there, but it's pretty tiresome stuff.