This is one of the best movies I have seen in a very long time. It is absolutely incredible. Before you run out and rent it, however, be forewarned: it's not for the faint of heart or weak of stomach. It's quite brutal and incredibly gory. In this, actually, it certainly occasions reflections on violence in movies and whether people like me have been desensitized to horror, because the violence is extremely aestheticized, and is actually stunningly beautiful in a really disturbing way.
I don't want to say too much about the plot because actually, the way it unfolds is one of the best things about the movie. One should enter into the film, I think, knowing as much as I did: that there's a guy who is convinced that aliens are about to destroy the planet, and in an attempt to thwart them, he kidnaps a man whom he believes to be their leader. Part of what drew me to the film in the first place, incidentally, is my fascination with horror movies where the monster looks just like a normal person. Zizek got me fascinated with this idea, that the ultimate horror is not the creepy green creature, but rather the evil that is nearly indistinguishable from the everyday. This movie handles the theme beautifully, weaving the theme of insanity into the film with incredible grace.
It's hard to explain what makes this movie so amazing - it's something about the way it uses cinema as a narrative mode. Plenty of movies look pretty, but what this film manages to do is use the actual image to produce meaning in the way akin to an incredible painting. It's really quite mindblowing. There's a bit towards the end that is especially amazing, throwing in visual references to other films and some documentary footage - it's one of the most incredible reflections on cinema as an art form that I've ever seen, and raises these really interesting issues about the relationship between film and reality. God, it really is an incredible movie. This is exactly what an amazing artwork does, I think - it shows you things in a completely unique way, producing meanings that cannot be articulated in any other mode. In other words, I cannot tell you in words what this film tells me via film, because the things it expresses cannot be fully translated into words.
In sum, wow. Absolutely amazing.