The film was a riff on conventions. You can't subvert a convention wholly or on it's various levels if you don't follow or allude to that convention in some way. It wasn't about giving you an original narrative (after about... 1200 BC, what has been?) it was about giving you a highly stylized visceral kick by playing with/against our expectations of pulpy crime/action movie/arthouse/music video/western/classic Hollywood motifs. Also, assuming you're right about the story, when was the last time you saw such a pedestrian story line delivered with such gravitas? Great sound design, great edits, and even if the arcs can be traced back to stories we already know and arcane genres (all stories can) when was the last time you saw those stories presented so inventively? How the film's finale was handled was incredibly bold even among the most provocative indie films, let along something that's getting this films distribution.