South African digital effects wizard Neill Blomkamp turns writer-director for this attention-grabbing sci-fi parable. Seems a massive flying saucer full of pathetic, crustacean-like aliens has broken down over Johannesburg. Since these starving, diseased immigrants from beyond the stars aren't exactly the cuddly E.T. types, they're banished to a slum-like refugee camp. Years later, when the government tries to evict them, things turn ugly. The story's little more than an effects-laden chase, but it's fresher than just about anything else you've seen lately.112 minutes R.