First things first - no-one gets to "be" Superman or Batman. The idea behind this game is that the DC Universe has suddenly been flooded with thousands of new superheroes. The cause of this outbreak is one of the plot's mysteries: perhaps the Government is on a vigilante recruitment drive, or maybe it's just Primark is having an end-of-season sale on spandex. Whatever the source, the upshot is that you're one of the new kids in town - fighting with the good guys, or alongside those dastardly forces of evil.