Critic A.O. Scott has a really fantastic article on Black Swan and Natalie in the NY Times. Those who are spoilerphobic, may want to tread lightly.
But in the end it all comes down to the actress, who seems, before our eyes, to be participating in the invention of a new kind of screen performance. In its various iterations, the Method has been about using voice and gesture to express a character’s deep psychological truth. Ms. Portman, like other young actors working with filmmakers who emphasize the visceral and the immediate, seems almost to reverse this process. Nina’s psychological state is evidently part of the artifice of “Black Swan,” but her body, subject to unimaginable (and sometimes unreal) mutations and mutilations, is the film’s ground zero of authenticity.