A rarity for a time travel film, in that this is one that actually thinks a bit of the details and cause and effect of time travel. To avoid the problems that the forensic science of the future poses, the crime lords of the future send back their problems to be offed by assassins of the past. The price they eventually pay is that some day their own older future selves will be sent back to be killed, resulting in a final big payday and 30 years of high living until that day arrives for them. But things go ary for one Looper when his future self (Bruce Willis) gets free in the past to try and hunt down a future super crime lord, and thus the chase begins.

Every detail of this time looping is thought out (save a bit of nipicking of all that gold and silver being sent back as pay now being duplicated in the past), save one that, while not showdd, is implied. That last matter is of the big crime lord- known as Rainman- himself. The problem is when Bruce Wills tries to kill him in the past, if he does so then the Rainman would never exist, which means he would neverbe alive in the past to kill him. But if he gets away and lives then then he still becomes Rainman. The only way things work is if on the first iteration that some other event else makes the man become the Rainman, but that is implied by the difference between the first iteration (the pre-Willis one) and the second iteration (the Willis one, the third iteration being the Younger Joseph Gordan-Levit one). The first iteration had no Rainman, the second did, which means that Willis second iteration killed someone after his final payday that set off the Rainman (I could tell you who but that would be a plot spoiler; easy to figure out once you watch it).

Anyway, this is a really good movie of the genre and it's about Time.