Saving Metropolis and Gotham City from the clutches of super-villains might be enough pressure for the average caped crusader but the cast of the forthcoming "Justice League" film also face another equally-terrifying foe: film critics. The film is the latest installment from the DC comics stable of super-heroes - a series which, with the notable exception of this summer's "Wonder Woman", has met with a less than positive critical response and has failed to match the box office of rival Marvel's biggest super-hero offerings.