Personality splits are standard-issue camouflage for most super-heroes, and the Marvel comics version of Thor is no exception. But Kenneth Branagh and the team of writers who have brought the super-hero spin on the Norse god of thunder to the big screen decide to largely ditch the whole alter-ego bit, as well as most of the usual trappings of super-hero origin stories that often cause them to drag with exposition. In their place is a movie with a split personality of its own.