I’ve not seen other “fake found footage” horror films (Cloverfield, Blair Witch) so I can’t compare to them. I suspect, though, that “mockumentary” movies such as Spinal Tap might be a better comparison. This is not a scary film; it is just scary enough to make the comedy work.
It follows a bunch of student filmmakers as they troll around (sorry) the Norwegian countryside, initially trying to get an interview with what they think is an unlicensed bear-hunter. Of course, this is the eponymous troll hunter, Hans, and despite their initial incredulity they get drawn into documenting his work.
The decision to make the camera crew students is inspired, as their enthusiastic skepticism is a great “key” to draw us in, particularly as they become more serious in their investigations. Likewise, the decision to play it straight, delivering a barely-attempted “rational” explanation for the mythical creatures without camp or jokiness means that we can get more involved in the drama so the laughs, when they come, are more satisfying.
The faux “we really believe this is true” silliness that bookends it doesn’t really work for me – I thought it unnecessary – but I’m sure it’ll work for some. In fact, I look forward to crypto-zoologists adding troll sightings to those of Yetis, Bigfoot, Nessie, Chupacabra and all the other non-existent creatures they pretend are real.