>>177094689>the mechanics actually make senseIn one interpretation of time travel's effects, but that's not the most likely interpretation. Realistically, you can't alter the past to change the present, because the present will have already changed by the past in your present (Novikov), or the act of traveling back will fork a new timeline from when you arrive (multiverse).
The biggest criticism I'd give of Looper is that it's unfocused. Many things are given attention which have little bearing in the overall plot: Joe and the hooker, Joe and Sara, the gat flunkie, Joe's past. Each of the character elements presented there could be given through other scenes. Ideally, it'd be a story about Future Joe told through Present Joe, with Present Joe maturing in light of Future Joe's personality, and deciding that the best way to prevent the suffering that Future Joe fears is to kill the both of them. Instead, we get a story about Present Joe's loose life and how it falls apart with the introduction of his future self.