It the third (after Oblivion and After Earth) of the "man, fvck this planet" trilogy, made by that nice man who made District 9. You're quite possibly aware of the premise - All the rich people live in a lovely satellite ringworld, all the poor people on Earth can suck it. Here comes Matt Damon to sort things out!
The story's not that much more complex than that, most of the attraction comes from good stunt casting - William Fichtner as evil factory boss! District 9's Sharlto Copely as a shaggy Afrikaner "operative"!* Some guy who I was convinced was one of the hobbits! - and from some excellent special effects work. It does have serious case of Moppets Wise Beyond Their Years, and also does sloow down at the end, quite literally in places - it's worth remembering that District 9 was in fact "brought to us" by Meaningful Slomo addict Peter Jackson.
I think I'd really like to see Neill Blomkamp direct a film written by a good sci-fi writer - until then this is a very watchable way to spend your time.
* As a white South African, Blomkamp is more than happy to play on the fact that audiences are quite happy to love to hate white South Africans. Arnold Vosloo cannot surely avoid his casting calls forever.