Although Tony Jaa's exhibition of martial arts mastery isn't wearing thin just yet, he has set his bar unusually high -- and now the tough part might be the attempt to clear it himself. Ong Bak 2 is the "sequel" to Jaa's stunning international debut, Ong-Bak, and his third international outing after the entertaining The Protector, but it contains only a fraction of the previous two's joyful invention.

Part of the problem may be the setting and story -- Ong Bak 2 really doesn't have anything to do with Ong-Bak and is set in Thailand's medieval past, and the lack of contemporary setting means less easy variety for props and fighting locations. Still, this could've been overcome, but it seems the movie also takes its story pretty seriously too, where the young son of a slain loyal general grows up with a band of outlaws and learns fighting skills that will help him get revenge against the government rebels who killed his family.

The film's pervading somberness fills up the space, which is considerable, between the handful of fight scenes. Those scenes themselves aren't terribly memorable, especially after seeing the mind-blowing stunts of those first two movies; this time, they are mostly one-man-vs.-gang fights with a bloodier edge, as more sharp weapons are used instead of fists -- a downgrade in the entertainment value, if you ask me. The climax features a glimpse of the fun gimmickry I hoped for more of, as Jaa takes on an opponent atop an elephant.

An argument could be made in support of the filmmakers' attempts to tell a more serious story, since most of the time the stories in these movies are trivial -- and since Jaa is the co-director here (alongside Panna Rittikrai), it may signal a seriousness of artistic intent on his part. But until those storytelling skills are refined, we shouldn't cease to expect the level of creativity that has helped propel any good martial arts flick to cult/legendary status, especially for a film featuring Tony Jaa.

(Released by Magnolia Home Entertainment and rated "R" for sequences of violence.)

Review also posted at www.windowtothemovies.com.