With the dirge-like “Death March”—a doomy, unrelenting slice of chillingly atmospheric heavy metal—Mastodon come out stomping with apt intensity for the Hollywood anti-hero flick they’re helping score. “Clayton Boys” picks up the pace with a few added darkly psychedelic effects, eventually pushing full speed into a punishing finale. “Indian Theme” gets wilder and more furious, replete with chunky, breakneck hooks, and “Train Assault” sets the scene for hurtling action with a wash of cymbal crashes and a crescendo of riffage.