Quentin Tarantino's bloody big-screen comeback Kill Bill butchered the box office competition over the weekend, opening at No. 1 with $22.2 million. It was the director's biggest debut to date and the fourth-best October bow ever. Last week's top flick, Jack Black's School of Rock, slipped to second with $15.4 million, but lost only 21 percent of its business. Joel and Ethan Coen's new dark comedy Intolerable Cruelty starring George Clooney and Catherine Zeta-Jones opened at No. 3 with a decent $13.1 million, followed by Good Boy! (No. 4 with a better-than-expected $13 million) and Out of Time (No. 5 with $8.6 million). In limited release, Clint Eastwood's latest directorial effort Mystic River earned a spectacular $591,390 on just 13 screens. It opens nationwide Wednesday.