Mirrors and reflections loom large in this dark treatment of an artist’s ability to lose herself in her art. In the end, the film doesn’t add up.  There is the plot, of course: a mystery placed in a pressure-cooker and split into several personalities; but there is also the performance of Natalie Portman: brave, as you’ve heard, but still not as good as her performance in Closer.  The film itself, doomed probably to wilt in its own hype, was very, very good - but nothing I’ll ever see again.The supporting performances were phenomenal.  Is Barbara Hershey a doting mother or an overprotective nutjob?  Is Vincent Cassel a challenging mentor or a vicious horndog?  Is Mila Kunis a rival, a friend, or…Natalie Portman?