I always get weirdly patriotic when people notice Norwegian movies.
Anyway, the movie is good -but a lot of its charm lies in recognizing troll stories and myths at least all Norwegians probably know, a lot of from the Asbjörnsen & Moe's Norwegian Folktales from the 19th Century. Kind of like our versions of the Grimm Brothers. Even if you dont know what a Tusseladd is though, you'd probably find it at least some parts entertaining. And yeah, a little Cloverfield/Blair Witch'ish, but I'd rather label it humorous.