I found this movie to be entertaining. It reminded me of Trollhunter, another movie on the same subject, but which was perhaps smaller in scale as it involved a small group of troll hunters rather than the entire government of Norway and its military. When it comes to science fiction or fantasy I tend to give more slack for the writing and I found this to be fairly well written and well acted. There were a few clichés about government leaning on the military as their first and only response to a crisis, but in an odd way it is a relief that it is some country besides the United States being portrayed as doing that. I thought the special effects of the creature and the scenes of destruction were pretty good, though I do not profess to be all that knowledgeable about the world of special effects. The ending of the movie seemed a little anticlimactic and not quite believable to me as far as the final plan to neutralize the troll went and the final scene of there being more trolls feels a slam to the earlier assertions that this was indeed the last troll in existence. But as I said at the outset, the movie held my intention and was entertaining overall. So what more could I ask for?
There's nothing very original about this, but it's got some likeable characters and really solid special effects. The explosions and fire of the military's offensive against the giant troll being the most impressive.