Joe is a looper, a hit man who kills people from the future in his present (the year is 2044). Time travel gets invented in the future and is outlawed immediately, so the mob uses it to dispose of people. Joe does his work gladly and understands the price that comes with this sort of job. During a regular hit, Joe's kill doesn't arrive on time, but when he eventually does, it turns out to be future Joe. From this point on, Looper becomes a chase, morality, and philosophical tale about sacrifice and the way things end up in circles, with plenty of violent action to keep you on the edge.
The visuals and sound in Looper are all top notch. The film has the look of a modestly budgeted picture, with practical effects (for the most part) and unique shots (camera shaking, tilting, panning, etc.), giving it an old fashioned look and feel. There tends to be a nice amount of care in the details, from Joe's apartment, to the diner he frequents. It may not be much to the average viewer, but it's something that I noticed and shows up throughout the film's entirety. These details could range from the machine in Joe's room that plays music, to the color of the cigarettes his girlfriend smokes. The details are not too much to fully distract us; they exist to show us how life is in this future, how things work, and how people live.
Speaking of people, the actors are all great. Special mention to Paul Dano for his small but memorable role as Joe's best friend and Jeff Daniels as Joe's boss (who essentially becomes a scene stealer in almost every scene he's in). Emily Blunt is also in this film and has a very active role towards the latter half of the film. Her performance really surprised me, but not as much as the performance of Pierce Gagnon, who plays the child of Blunt's character, Sara. Without giving anything away, Gagnon (as Cid) does an incredible and convincing job as a young boy who is a lot more than what he seems. Another special mention goes out to Willis, who doesn't play the usual wise guy this time around. Levitt and Willis channel and embrace the roles they are given (which is technically the same role), with Levitt really channeling Willis and Willis playing his role as seriously as can be. Older/Future Joe is such a dark character, that whatever preconceptions you may have of him at the beginning will change by the film's end.
Speaking of the end (which I won't speak about), Looper doesn't end the way you might think. The easiest way to put it is that Looper has an unexpected ending. Much of what Looper does can be considered unexpected, as well as unconventional. The film does not glorify anything and there are certainly no heroes to be found. The film also plays with the dynamic of time travel very well without getting too deep into the subject (the film outright lets the audience know that it isn't going to go into it). While the film can be simple, it isn't structured in simplicity. When time travel is dealt with, things get tricky, things get complex, and things get philosophical. While one can get many themes out of the movie, I think the two themes that remain constant and understanding are choice and cycle. We all have the power to choose and make things different, regardless of what someone says about the future. We also have the choice to do good and bad things, and sometimes we do the wrong things because we think we're doing them for the right reasons. And as for cycle, well, everything goes in a loop (no pun intended). The final line in the film seems to sum up the main points and ideas presented in the film (or at least put a more significant layer onto the film) by emphasizing the last theme presented in the film: sacrifice. With choice comes sacrifice, and these things tend to go in a cycle. But that's just one interpretation.