As a critic and as a viewer, I can appreciate that different genres of film have different obligations to the audience, so it's really not fair to judge all genres on the same metric. For the price of my ticket, as long as the movie about aliens has good visual effects, sustained tension and a script that doesn't rely on snarky one-liners, I'm satisfied. So, when a movie like District 9 comes along that manages to do that plus a really compelling story and just the right amount of social commentary, I'm thrilled.

Writer/Director Neill Blomkamp made a lot of good decisions for District 9. Given a less shrewd (or original) director, I think this film would have come out like any number of other sub-par science fiction pieces from the past decade. First and foremost is his choice to use the hand-held camera technique instead of steady shots. District 9 is a movie about the chaos and nightmarish conditions of creatures from another planet shoved into a shanty town. It certainly wouldn't benefit from the cold indifference of a camera on a crane.

I also really like what Blomkamp did with his aliens. They're certainly strange, but familiar enough to still be sympathetic. Little aesthetic choices end up amounting to a certain amount of elegance and functionality, like the fact that they communicate in a series of gargles and clicks instead of a distracting made-up language or an annoying pidgin of English and alien words.

The most inventive element of District 9's "prawn" aliens is that they defy the cinema convention of super-smart and often smug overlord types. The aliens who arrive in this story are working-class families who only showed up on our planet because their ship stalled and they were running out of provisions. They don't come from a utopia and they aren't any more or less "civilized" than their human contemporaries. District 9 isn't an alien invasion, it's an interstellar refugee crisis.

Thankfully, District 9 doesn't beat its viewers over the head with social commentary, either. There's enough for us to draw clear parallels between the prawns and any number of humanitarian atrocities in our own species, but it also doesn't forget to be a thrilling sci-fi action movie. The pacing is excellent and the tension builds from a simmering start to an explosive finale.

District 9, for all its virtues, is not a flawless movie. Some of the characters, like the leader of an unmistakeably Blackwater-like private paramilitary group that acts as a security force for the prawn slum, are just too broad. I'm also not sure how I feel about the Nigerian crime lord who makes a small empire in the slum. On the one hand he's effective as an unpredictable force in an otherwise bleakly lopsided struggle, but he's also just too much of an outright villain to feel like he fits in this story. A little depth or even sympathy might have rescued him from being a stock monster.

District 9 is a thinking viewer's action movie to be sure. It's exactly the kind of film we need as a late-Summer release, allowing us movie-goers to transition from the pure popcorn of the hot months into the more thoughtful, or at least toned-down, pictures of the Autumn. It's hard to tell how much lasting appeal it's going to have. District 9 is more than good enough to join the pantheon of great science fiction, but I think it'll more often be shelved alongside the likes of Children of Men than most movies about space ships, aliens and lasers.