Identity of pusher? - BIG SPOILERS!!
I've seen many reviews of this where they class the battle between Bulcsu and the pusher as a straight fight but there are two theories I'd like to discuss about who or what the pusher is:
1: Bulcsu is the pusher, in a Fight Club style the railing battle is the equivalent of the gunshot to the cheek at the end of FC, a symbolic 'killing' of another personality. He and the pusher each dress alike, there's the scene where he closes his eyes and lets the pusher pass, and his dream where he goes in the small tunnel and sees the pusher (his character had not seen the pusher or his appearance previous to this) all point to this.
2: I'd described the mood of the film to my brother who saw it with me as being like Pi meets Twin Peaks (got the owl), and perhaps the pusher, like Bob in TP, is a malevolent force representing violence and aggression. There's the quote about spending enough time around aggressive people that you become aggressive yourself (adds to theory 1), and the appearance of the pusher running towards the scene where Laci slits the guys throat.
Any thoughts?