If you don't have plans to see this movie, you can check the spoilers here and then come back.
This movie was quite captivating, visually stunning, and extremely well-crafted, yet the critic in me just couldn't get past the extreme disconnect between large portions of the story and simply enjoy the ride. It starts out balls-to-the-wall with an utterly unique and exciting plunge into a fictional world that felt more real than any I've seen in a long time as Neil Blomkamp really took the time to build the backstory and feel of these alien refugees on Earth and utilize the faux-documentary routine more effectively and sincerely than I think I've ever seen it. The "mundane" scenes of the aliens' earliest interactions with humans struck quite a chord and were deeply affecting; the aliens and the way they moved, talked, etc. was so unsettling and yet familiar. I really dug this first portion as I had no idea where Blomkamp was taking me, but it was a journey I'd never been on, exploring the idea of extraterrestrials as just folks. However, once the story kicks in, everything veers harshly into cliched sci fi action movie territory, complete with the ruthlessly evil stepdad (they should have just gotten Alan Dale to play him), the odd couple buddy team defying the odds, the science whiz kid who saves the day, and so on. The thing is, as popcorn movies go, it's still quite good, with really great effects, sharp pacing and excellent action sequences, however it just didn't jibe at all with the earnest and deep film I was expecting. My critiques aside, Sharlto Copley was amazing as the lead and the one tether between the two halfs of the movie that felt natural as he adapted perfectly from one role to the next and didn't allow his character to become lost in the tonal shift. It didn't just feel like he was playing an everyman onscreen, he really did carry an honesty into everything he did, whether as the goofy stooge, the panicked fugitive, or even the reluctant hero. I have nothing but praise for Copley's nuanced and spirited performance; he's going to be a big star. Ultimately perhaps the most disappointing thing about District 9 for me was that I think had they made the firm choice to be a light-calory action movie from the start it would have been a good one, as Blomkamp clearly knows how to craft a blockbuster and Copley has a great sense of timing to toss out the one-liners. On the flipside, I was totally buying into the more down-to-earth angle, so I would have loved to see more of that too. However, when the two worlds mashed up against one another, I didn't feel fully satisfied with either. I can't rank this too low because as I said it only really let me down from a critical standpoint and from a pure entertainment one held up pretty well, but man, I sure would have liked to rank it much higher.