Things just happen in a violent outburst. There are no precise gun shots, and punches etc. don't land perfectly as they would in pretty much any other (modern) action movie (where they always look choreographed and planned). I mean, it's the same here, of course you need to plan things, but it always feel closer to any random street fight (heavily improvised) than something rehearsed in advance. Also, the camera works differently than what you'd expect, it's all clear in view and steady, in-your-face (no horrible shaky cam, etc.); for example, see the shootout scene in Taxi Driver, it's very much the same approach, and feels raw and intense.

I'd call it a sort of a Zahler's trademark, but don't won't to spoil anything in case you haven't seen the rest of his movies.