You're right on the money, Alex. The characters are paper thin, especially the husband, but the atmosphere and scares are top notch. I have to say, though, that the final chase scenes were a step down from the scenes in the house. I was more infuriated than exhilarated. Up until then she was behaving quite realistically, for a horror movie, only to suddenly turn into an idiot. But everyone should give it a try. It's one of the better horror movies of the last years.