I watched District 9 last night at home. It is a really really cool movie, produced by Peter Jackson and shot in South Africa. It is a science fiction with a lot of undertones about xenophobia, fear, war crimes, etc.
The last third of the movie became kind of ridiculous, with bullets flying everywhere and never seeming to hit anyone, which detracts from it. The movie did a great job with a documentary-style realism that made a pretty fantastical scenario seem plausible, but threw it all away to make a "good" action scene with thousands of bullets shot everywhere and the main characters escaping unharmed. It felt more like a James Bond movie at the end than a good sci-fi film. There are a number of narrative holes that I would hope to have filled in with a sequel, such as why the aliens appeared so disorganized and dumb despite having such great technology. Why did the "smart" alien with the red vest seem so much smarter than the other aliens. Why was he able to work to make a ship while the rest did nothing but goof off all day?
Also, I'm currently reading Guns, Germs, and Steel by Jared Diamond, so I'm surprised there were no interspecies diseases being passed about that would have either wiped out the aliens or wiped out the humans. All in all there is a lot to be answered.
I was a big fan though of the whole "discovery" process where the two species are learning about each other and the various stages of human excitement and wonder at the aliens, to eventual frustration and hatred.
Also the acting was for the most part very good and believable. I love watching good actors, they really nail the facial expressions and body language of the person they are portraying.