Joseph Gordon-Levitt and Bruce Willis star in the latest science fiction film that centers on time travel, Looper.

The film takes place in the year 2042, where a hired assassin called a "looper" eliminates targets sent back from 30 years in the future; where time travel technology exists. Although it's been outlawed in 2072, the mob secretly uses the technology to cleanly dispose of anyone who may be a threat to them.

Gordon-Levitt plays one of the top loopers and makes a wealthy living from his job; but he's taken by surprise when his latest target ends up being himself (Willis), sent back from 2072.

The film opened on Sept. 28, 2012; and also stars Emily Blunt, Paul Dano and Piper Perabo.

The film is already getting great reviews, and it may ultimately make this list; but, for now, check out the trailer below and click through for our picks for the 10 best time travel films of all... er, time.