There are a few plot holes in Looper's time travel mechanics, as there are in any time travel movie, but Willis' line is aimed more at the audience than the character he's speaking to. Johnson is more interested in the psychological and emotional complexity of time travel than the mechanics, like the complicated stand-off that develops between Gordon-Levitt's character Joe and Willis as his future self, who manages to run before Young Joe can take him out. Young Joe is mad because Old Joe got to live his life and is now messing with Young Joe's future, while Old Joe is mad that Young Joe won't listen to his enlightened perspective on what he should be doing.

It's easy to notice the tics and mannerisms that Gordon-Levitt took from Willis and worked into his performance -- the gravel in his voice, the wry smirk -- but even a slight over-emphasis on these tics (Gordon-Levitt may evoke more Willis than Willis) doesn't distract him from making Joe into a fully-realized performance. The smirks stem from a brash personality that Willis reflects, with a hint of resigned desperation. Even if you don't necessarily "buy" that Gordon-Levitt will turn into Willis, because both actors are so recognizable (even with Gordon-Levitt's weird facial prosthetics), they still create a palpable electricity between them that crackles in a pivotal diner confrontation. Willis, to his credit, seems relaxed and emotionally invested in the material, even if he's in less of the movie than his top billing suggests.

In terms of performance and core story, Looper is exciting, but the film is almost capsized by an excess of ideas. There's an idea in Looper that feels like a movie in its own right, but it's only a smaller element here. Not only is it a bit tough to swallow, but its inclusion in Looper seems lazy, an easy shortcut to avoid having to explain certain things. Less important but still a little distracting is the world of the future, which is never as convincing as other sci-fi dystopias. It's right on paper to make the future a blend of old and new influences, but there's still a weird design gap between current cars and future jet bikes that draws attention to the gimmick, and its awkwardness is only emphasized by the amount of time the film spends away from all of it. Johnson's skill in the action beats also varies, with some sequences coming off stylish, and others over-cut and clunky.

With so few ambitious and creative films being made in America, it would be easy to point to Looper as a breath of fresh air, and it is. There's no denying that this is an impressive picture, full of intelligent ideas and exciting concepts, as well as several great performances (Emily Blunt, Noah Segan, Paul Dano, Jeff Daniels, and young Pierce Gagnon are also fantastic, in addition to Gordon-Levitt and Willis). Still, invention requires finesse, and some of the movie's side ideas should probably have been trimmed or removed in order to focus on the parts that stand out but stand together. When the dust settles, Looper manages to close its own loops, but it's an uneven road around.