I'm a guy who nearly always prefers a heavy, downbeat ending, in which the audience is forced to grapple with a problem that has no apparent solution, as opposed to endings that are happy just so that we can leave the theater in good spirits with nothing nagging at the conscious. However, District 9 makes me wonder how I could ever feel that way. This film progresses from frightening to angering to disturbing to saddening to heart-wrenching without missing a beat. It is so viscerally and emotionally intense that even I found myself hoping that somehow there could be a happy conclusion to the events. I almost didn't even care how.

Twenty-eight years ago an enormous alien ship arrived at Johannesburg, South Africa. It floated over the city for three months, doing nothing. We finally decided to enter it and see what was inside. Helicopters were sent, and inside, the soldiers found the ship packed with malnourished aliens, apparently abandoned by their leaders, groveling about miserably. The government cordoned off a slum for the aliens to live in, and problems arose. A mixture of dangerous acts of mischief on the aliens' side and prejudiced resentment on the South Africans' side resulted in heated relations between the two species until finally the South African government decided to evict every one of the aliens, moving them to an outdoor-prison-like area away from civilization. We follow Multi-National United (MNU) director Wikus van der Merwe as he leads the violent effort to relocate the aliens that now number in the millions. Things don't go well. The plot escalates drastically when Wikus stumbles upon an alien substance that causes him to slowly metamorphose into one of them. It also turns out that this substance is the aliens' only hope of ever returning to their home planet.

The single most powerful driving force of District 9 is its evocation of the trauma of great change. Every major plot point hinges on this theme. First it is the arrival of the aliens. The images of their ship hovering motionless above Johannesburg are utterly unsettling because of both the thrill of encountering an alien species for the first time as well as the anxiety of not knowing why they are here. Then the focus is on life with the aliens, which turns out to be an incredibly difficult adjustment for the people of South Africa, many of whom just want them gone. What results is civilian violence and government oppression against the species, which seems, on the whole, to be more frightened and disoriented than anything else.

In fact, this change that the aliens face is an equally important part of the story. This is a species that has no idea how our world works. What seem like innocent acts of recreation to them are at times terroristic to us. Their slums are overrun with South African gangs, taking advantage of their weaknesses in order to procure from them their weaponry. They are constantly harassed by the MNU as well. It was a brilliant move by the filmmakers to spend so much time on the aliens' point of view because, while it is certainly frightening to suddenly have an alien species living on your planet, it is exponentially more terrifying to be that alien species, stuck on a strange planet whose inhabitants generally bear only ill will toward you, seeking to exploit you for their gain while simultaneously shunning you from their civilization and forcefully relegating you to the least livable places it can find.

The horror of drastic and unprecedented change does not stop there, though. It is also found, perhaps at its most extreme, in the plotline of Wikus' metamorphosis. Wikus is exposed to the substance that changes him while simultaneously serving eviction notices and searching aliens' houses, all in a sickeningly joyful manner. What he does not realize is that it took the aliens twenty years to extract this fluid from miscellaneous debris from their ship, and it is the one fuel that will allow them to power their ship and leave Earth. Wikus unwittingly sprays himself in the face with it while messing with it blindly. The metamorphosis begins with vomiting, sweating, and black nosebleeds and progresses to the loss of fingernails. Wikus wraps his hand in gauze, hoping the problem will fix itself, but after vomiting a black, viscous substance all over the cake at a party and subsequently being taken to the hospital, the gauze is unwrapped to reveal a fully functional alien hand.

As if this physical change was not upsetting enough (to both Wikus and viewers), Wikus now finds himself the subject of unbelievably cruel MNU experiments. Paying no mind to Wikus himself, the MNU scientists begin testing the functionality of Wikus' arm. They test its ability to feel pain. Then they test Wikus' ability to fire the aliens' far-advanced weapons (which sense the DNA using them, rendering them useless to humans besides Wikus). When he refuses, pleading with them to not make him do any more, they shock him with a cattle prod, literally forcing his finger to pull the trigger. Then, to Wikus' utmost dismay, they make him kill a captured alien with one of the weapons. Finally, they take Wikus to the basement and prepare to dissect him alive, at which point he escapes. With the entire MNU after him, his only place of refuge is the last place on Earth he would want to be: the alien slums. His life has now been flipped completely.

It is at this point that Wikus comes to know and understand the aliens intimately. He ends up with the very alien from whom he confiscated the fuel-fluid, and he learns that his metamorphosis can be reversed if the aliens can get him up to their ship. This, of course, would require the fluid -- which is being held four levels below ground at the MNU headquarters. Suddenly Wikus has a great vested interest in the aliens' chance at escaping our world, and the movie borders on the action genre for a bit as he and the alien attempt a two-man assault on the MNU in search of the fluid, an operation made plausible by the awful power of the aliens' weaponry. I say this segment borders on the action genre because, though there is plenty of action, the film's focus is on the disturbing nature of the situation. Wikus' demeanor the whole time is not one of vengeance or thrill-seeking but of desperation. The violence is not entertaining but unsettling, as the weaponry Wikus and his friend are using causes the enemy to explode into tiny bloody bits. There is nothing glamorous about the action here.

The film's final act consists of selfishness and selflessness, betrayal and hope, overbearing sadness and tearful happiness, all masterfully combined into a perfectly consistent mixture. It is emotionally ripping, yanking the viewer in every direction. This is not only a flawless execution of maximizing the film's effect on the viewer; it is, more importantly, a fitting way to end a movie with such a heavy focus on how psychologically devastating change can be. When one's world suddenly turns into something far different from what it has ever been, the resulting state of mind will be one or more of many extremes. District 9 magnificently seems to capture them all.

Throughout the film's many changes of pace, Neill Blomkamp's directing remains practically perfect. It begins as a documentary of the aliens' arrival and our eventual attempt at relocating them. The appropriately gritty look of the film during this portion of it accentuates our inability to understand the aliens and their reason for being here. Smartly, this distance is retained throughout most of the film. Even after the movie sneaks in non-documentary footage to the point that most of the events on screen are happening now, the grotesque images are mostly kept brief and unclear. This creates an authentic feel to what is presented on screen instead of an attempt at showing off the special effects, which would have distanced the audience from the narrative. That's not to say there are not some close-ups and clear depictions of aliens and of Wikus' metamorphosis. There are, but all such depictions are used only when appropriate and always matter-of-factly. Blomkamp trusts in his and co-writer Terri Tatchell's ability to craft an engaging story as well as in the audience's ability to give themselves to such a story without requiring shiny close-ups of every visual effect. The special effects are wonderful, but Blomkamp uses them exclusively to advance the story, never simply to show off.

Watching District 9 is an exhausting experience. One minute you will be frozen with suspense, the next you will be gripped with horror, and then you will be torn between emotional polarities. I cannot recall a movie that has created such sympathy for alien characters nor one that has portrayed such cruelty against them. This is science fiction at its most effective. It presents us with something new, but instead of using this new thing as a spectacle, it uses it as a means of examining human nature. When you watch this movie, you will be unable to turn away -- not because it is fun but because it puts so much at stake.