The movie goes great until a certain point which is actually the ending. All the building up - mom being biologist, the drawings on evolution, the creepy nanny, creepy books- creates a great puzzle and a variety of theories for the viewer. It gives the feeling of suspense beautifully but the ending doesn't fulfill all the work that was put in. It's not even a "think hard you'll get there" kind of ending. It's just... disappointing.