The Dardenne brothers, Jean-Pierre and Luc, are known for their low-key, plot-light, character-heavy tales of survival, usually played out in a small Belgian town that serves as their spiritual microcosm and often focused on the struggles of children to make it to adulthood in one piece. The Kid with a Bike, which won a top prize at last year’s Cannes Film Festival, continues down this path, though Dardenne purists may find fault with the film’s upbeat conclusion, a contrast to the harsher endings of their earlier efforts.