There are so many layers to this film that it's very hard for me to tackle a review and not feel like I'm doing someone a disservice that may not have seen it. This is one of those movies where walking into it with no preconceived notions is a benefit, as it is also one of those movies that will stay with you long after you leave the theater.
What I can do is give the basic outline (which perhaps anyone could do from the trailer) but here it goes anyway:
Aliens come to earth and their ship drifts to a stop outside of Johannesburg South Africa. After waiting and waiting for "first contact" humans decide to cut their way into the ship. Once inside they find deplorable conditions, sickness, and despair. The aliens are then brought down to the planet in a humanitarian effort to save them (and naturally to be exploited for tech and other goodies). Once here, it is obvious they aren't welcome in much of the city, so they are moved to slums on the outskirts. Control and security of this area is handled by a private firm (like a combination of Blackwater, Haliburton, and Raytheon) who keeps the slum a demiliterized zone. Crime becomes rampant as Nigerian gangs infiltrate the area in an attempt to buy and sell weapons (which only work with Alien DNA much to the chagrin of that big firm controlling the area too) and Sex (Which thankfully they left how exactly aliens are pleasured by human women to the imagination).
That was the very well handled exposition they give you in the first 8 minutes. The rest of the film focuses on Wikus van der Merwe, a rather bumbling mid level company bureaucrat who is tasked with moving the aliens out of the slums and into the equivalent of a concentration camp. He is a contradiction, at the same time both likable and awful. His ignorance to what is really going on around him led me to be somewhat sympathetic to the character, but his actions lead you to despise him and the rose colored world he allows himself to exist in.
They go into the slums in very UN looking vehicles to have the aliens sign their consent to be moved. This is not a legal act and one such alien recognizes this. His name is Christopher Johnson... don't ask, I have no idea.... but he and his son become entangled with Wikus for the rest of the film due to a mishap and resulting cascade of events.
And that's all I will give away of this remarkable film. This is a landmark in Sci Fi and at the same time a fantastic "Fuck You" to Hollywood big budget toy movies and re-hashes. It has all the wiz-bang of sci-fi, with none of the techno-babble trappings. It has all the action and cool tech of a summer blockbuster with a quarter of the budget, it doesnt dumb down for the audience or feel the need to spell out everything. It is a film exploring something as epic as the human condition yet hiding in what appears to be a small story of two people on opposite sides of a fence. Finally, its exploration of interpersonal relationships and family is surprisingly emotional, and one really does find the complexity of compassion for the two big parties involved. There wont be too many that aren't moved by that last frame of film.
Instant classic. My highest rating.
**Edit... One final note... The aliens aren't named in the film. However, a term is used for them as slang. I feel weird referring to them in this way though, so I refrained from doing so in my review.