I saw it on DVD last week. Meh - it was like watching a bad remake of Apocalypto. There were some details that the director and screen play writers should have really paid attention but didn't. Two small things that really got me - cave man talking about love and its place in one's heart; the other one was when one of the caveman was thirsty and in need of water even though he was walking through snow.....
But overall, once I blocked all common sense the movie was OK - 5/10