I would sum this film up as a shallower remake of the Wicker Man set in Scandinavia. It won't be all that creepy if you have any acquaintance with pagan or Celtic lore since it's all wildly improbable, if not Biblical, in its grim depictions of life as a pre-Christian nature worshipper. I sincerely doubt that spirituality has always made people as unhappy as the Church seems to have done of late.
Personally, I wasn't so blown away by the strong aesthetic sense that seems to have amazed the rest of the critics. I'm more interested in character and plot and the film is extremely - deliberately - weak on both. Why do so many of the top films of the 2000's seem to fare better off as music videos, I wonder?
Pugh makes a strong visual actress and she gets as much mileage out of the nonexistent script as anyone could be expected to do. I'd love to see her in a film that wasn't designed for MTV.
You might prefer to watch this while ironing or doing some other mundane chore since the long musical scenes won't hold your attention, I don't think.