Though it's based on a science-fiction novel by Steven Gould, Doug Liman's movie feels very comic-booky. It's punctuated by action scenes, a car chase, explosions, and shoot-outs -- none of which are very original or visually compelling, despite the seemingly singular notion of "jumping." It doesn't help that Christensen makes a vague protagonist, with his motivations for stealing money from banks or beating up bullies remarkably banal (essentially, he does it because he can). Though he gets nervous when Roland shows up with a big electric stick that's part cattle prod and part taser, he's blown off the screen (metaphorically) when another jumper, Griffin (Jamie Bell), shows up.
Witty, wise, and charismatic, Griffin is a more exciting potential hero than David, but he's mostly used as a source of information: He has actually looked into what it means to be a jumper and has learned history, considered moral responsibilities, and even figured out a strategy for resisting the Paladins. David is less able to consider nuances, but that's what makes him a "hero" -- at least in his own mind. As he says, "I used to be normal, a chump like you." Now, he's considerably less interesting, even if he doesn't know it.