You're not always entirely sure what is happening in Tony Jaa's new movie, but there certainly is a lot of it. In this sequel-in-name-only, the martial-arts maven plays Tien, a scion avenging his family in a 15th-century Thailand marked by arcane hybrid fighting styles and a numbing sepia murkiness. Flying-fist connoisseurs may appreciate his journey from training with bandits to battling the warlords who killed his father, but crossover fans tickled by Ong Bak's spark and humor will be disappointed here. While Jaa clearly hasn't lost any of his stamina in the six years since he starred as a different underdog in the original, his first outing as a director is confusing, with distractingly muddy storytelling and wildly varying styles from scene to scene. Thrills do come from acrobatic antics with an alligator and on an obliging elephant; a kick fight conducted mostly on the ground; and an engaging assortment of pummeling in a multilevel thatched village. The movie would work better as a highlight reel. While Ong Bak the first replayed shots from a second angle, here the gimmick is replaying in slo-mo—which only calls attention to the film's slog.