Like cinematic dynamite, "City of God" lights a fuse under its squalid Brazilian ghetto, and we're a captive audience to its violent explosion. The titular "favela" is home to a seething army of impoverished children who grow, over the film's ambitious 20-year time frame, into cut-throat killers, drug lords and feral survivors. In the vortex of this maelstrom is L'il Z (Leandro Firmino da Hora--like most of the cast, a non-professional actor), self-appointed king of the dealers, determined to eliminate all competition at the expense of his corrupted soul. With enough visual vitality and provocative substance to spark heated debate (and box-office gold) in Brazil, codirectors Fernando Meirelles and Kátia Lund tackle their subject head on, creating a portrait of youthful anarchy so appalling--and so authentically immediate--that "City of God" prompted reforms in socioeconomic policy. It's a bracing feat of stylistic audacity, borrowing from a dozen other films to form its own unique identity. You'll flinch, but you can't look away. --"Jeff Shannon"