I liked the jarring sound design which worked well in particular with those "thick", dense or oppressively positioned shots of Phoenix walking despairingly through city traffic and on trains. You get a sense of the city on top of him.
The soundtrack was a little uneven though.
Hard to think of anyone but Phoenix playing the lead. Intense as fuck, but then he has everyday, natural quality especially in the scenes with the mother.
Not sure about the ending. The ambiguity could almost be read on a parodic level.
Ramsey's work is never less than cinematic,her pitch or tone may be a little overtweaked. Still, visually rich.