Looper seems to upset dedicated nerds; people who’ve read The Silmarillion from cover-to-cover, people who like “hard sci-fi” – think Roman from Party Down. Rian Johnson’s time-travel flick annoys these people because it doesn’t play fair with the rules of time-travel, and isn’t interested in explaining or caring about those rules.
I’m also a gigantic nerd, but I’m not troubled by Looper’s time-travel mechanics (there is one moment that I could have done without – Bruce Willis’s Joe describing the Rainmaker’s artificial jaw sticks out as being an oddly specific piece of information). Looper doesn’t want you to nitpick the details of how time-travel works, and instead is more interested in providing haunting scenes like the “looper” watching his body disintegrate in front of him, gaining 30 years of memories of disfigurement all at once.
That comment of Willis’s I mentioned above – it feels clumsy, something out of a weaker movie. But without it, would I have spent the middle stretch of Looper dreading the outcome of a narrative with few sympathetic characters? That twisted knot of fear in my chest, born of full engagement with the story, is more powerful than any internally consistent system of time-travel could hope to be.