I have been very surprised to see the numerous bad reviews of this film and thought I should really add my comments to help address the situation. This film was absolutely petrifying - I was gripped from the first moment until the end. The eerie setting, the great acting by all the cast in particular Sean Bean and the lovely Maria Bello and the original idea all mark this film out as something special. I love the concept of this 'underworld' and the hark back to ancient Celtic mythology where the mother has to go to save her daughter - wonderful stuff. They really should make more films like this. This is a subtle horror movie and I can only imagine that the people who gave it such low ratings must have been hoping for a George A. Romero-style zombie fest. However, there are a few issues with the ending and certain plot lines that didn't make sense to me (for example, why does the mother jump into the water holding the girl when she was perfectly willing to let the girl go on her own before Sean Bean showed up?) The underworld itself was a dreadful looking place and the twilight-yellow tint on the camera lens made it seem like an alien landscape. Maybe 10 out of 10 is a little generous but overall I found this to be a very good and gripping horror movie, the best I have seen in many years.
