Your average swords-and-sandals battle film is a huge, big-budget undertaking. All those extras, costumes, props, coordination, and, in the modern age, digital post-production. Writer/director Neil Marshall’s Centurion — set in the second century A.D., as the Roman empire attempted to conquer the northernmost reaches of Great Britain, running into fierce opposition from the Pictish peoples who then populated the region — doesn’t skimp on the action or the bloody battles. But Marshall managed to make it for a fraction of the cost of overblown epics such as 300 and Gladiator by dialing down the scope and telling a smaller story, which works to the film’s benefit in ways far more important than the financiers’ bottom lines.