I watched this film over two days. The first day I was really tired and I found it quite lengthy and boring, but the next day it seemed much pacier. I think the strongest moments happen about two thirds into the film, at Alexis' birthday party. It makes you understand everything. In the end I quite enjoyed the subtlety of the film, while simultanously disturbed by the way so many things are left in the dark, unsaid.
Excellent character-driven indie drama centered around a superb performance by Maggie Gyllenhaal. There are no easy answers and a lot of very believable loose ends, the naturalistic writing and performances lend it a very compelling authenticity that few films achieve. It does drag in places, but all in all this is an extraordinary effort from writer-director Laurie Collyer.