From armies of vengeful undead zombies to armies of death-defying Spartan warriors, director Zack Snyder was hell-bent on proving his ability to deal with crowds, particularly those on movie screens and those who fill the movie theater seats. From a career that began in commercials, Snyder utilized his technique and insider’s perspective in service of a greater, more engaging thrill, when he giddily riffed on consumerism in a remake of George A. Romero’s “Dawn of the Dead” (2004). Whereas the movie careers of many of his peers in the glossy world of commercials extinguished while trying to