Ong Bak was arguably the world's greatest demo reel, consisting of a series of spectacular, innovative fight scenes with a very, simple story built around them. Tum Yung Goong was basically the same movie but better made. Ong Bak 2 represents a signifcant leap in realm of martial arts action but reflects severe stagnation, perhaps even regression, in terms of overall filmmaking.
SXSW Review: Tony Jaa's ONG BAK 2