Where were we again? And other questions. You know you've got movie problems when the trailer makes more sense than the film. The intriguing ad for District 9, the debut feature from Vancouver-based director Neill Blomkamp, features a crab-faced alien being interviewed on camera. Someone asks, "Why are you here?" "We just want to go home," the creature replies in alien speak. Interesting. Too bad it's not in the movie. Whoever edited the trailer understood the idea's potential better than the people who made this utterly incoherent sci-fi ramble. As actually made, District 9 turns out to be a jumble of half-baked concepts, special effects, and various movie conventions lashed together like a log raft. When it's over you'll still be waiting for an answer to that question: Why are you here? And by that time you'll probably include yourself in the bargain. Aliens and immigrants District 9 is at least the second movie to play off the double meaning of the word "alien." You may remember 1988's Alien Nation, another flick that featured outer space visitors who quickly become a despised underclass on Earth. District 9 sets up the story with plenty of newsreel footage of the alien ship's arrival over Johannesburg, South Africa -- director Blomkamp's original hometown as well as a loaded location for a tale of a persecuted minority. The bipedal crustaceans are quickly dubbed "prawns" (Futurama fans may think fondly of Dr. Zoidberg) and settle into a squalid shanty town existence, hated and feared by locals. We're all set up for what is to come: the mystery of their origins, the true reason for their Earthly exile, the various reactions and devious purposes of their reluctant hosts, the possibility of conflict. Almost none of it comes. Having set up its promising premise, District 9 wobbles off in any and all directions. Chiefly it tells the tale of a mousy little bureaucrat (Sharlto Copley) assigned to relocate the aliens, who becomes contaminated by a mysterious fluid and begins a strange transformation. Too bad he's not very interesting. One is reminded of those movies about civil rights in which a white person is placed in the centre of the action to goose the mainstream box office. Meanwhile we are patiently awaiting answers about the aliens -- who they are and what their presence means. Here's a spoiler: don't hold your breath. A lot of questions District 9 offers sequences seemingly assembled at random. An evil corporation with the spectacularly unimaginative moniker Multi National United is fascinated by the aliens' weaponry, and for awhile the movie is about their evil schemes. Nothing much comes of that. District 9 variously tries its hand at being a social critique, a conspiracy yarn, a buddy movie, and a sci-fi action shoot 'em up. Some people seemed to like that last one. The laziness and general incoherence of the script is astounding. Feel free to pass the time by asking yourself questions: What is the mysterious fluid Copley discovers -- space ship fuel, or a substance that causes alien mutations? Or a dessert topping? How does the most hunted man in the world wander around largely undisturbed? Why does an "accelerating transformation" mysteriously stop accelerating? And considering the amazing ability of the alien weaponry, why are the aliens dumpster diving in a squatter camp, being pushed around by pop-gun-toting humans? The latter is a particularly curious mystery, but it's typical of District 9 that it just sits there in the middle of the movie like a lump of uncooked batter. Even the whole aliens-as-illegal-immigrants concept, so promising in the trailer, turns out to be no more than a convenient plot device, introduced and left undeveloped, like almost every other script element here. Local origins Blomkamp is a real local success story. A Vancouver Film School grad and star of the local visual effects firm Embassy, Blomkamp made a short that caught the eye of, among others, producer/director Peter Jackson. District 9 is an expanded version of that short. Boy, does it show. The movie is like two jet engines and a tailfin duct-taped to a tricycle. It's been suggested that the script leaves room for a sequel. In fact, District 9 plays like the sequel to a movie that hasn't been made yet -- one that actually explains the concept. Note to Mr. Blomkamp: Go back and watch the trailer. Then answer the question.