Most 70s (and 80s) Kong Kong martial arts films barely function as movies; usually there are a few well-planned fight sequences, but the plot is scraped pretty thin to fill in the gaps between those nodes -- like porno films, really.
But this one does several things well. Most overtly, there is the direction and choreography, which confines each combatant to a 'style' -- it's really based on Chinese circus acrobatics and comedic theater, but the effect works.
Second, there is the language of the camera, which uses some impressive techniques(even by today's measure), changing projection speeds from real time time to slow motion, and from unfiltered to filtered views to depict story direction toward the past or toward the future.
Least overt, but most powerful and unexpected, is the construction. The winner of this contest is determined by who 'unfolds' the story. The master (the writer) sets up a game where the lead character doesn't know who he's seeking, which is the same situation we viewers find ourselves in. One by one, he figures out who is who, at the same rate we find out who is who. It all follows a tragedy/noir arc. The ending tends toward irony, a la "The Sting". Much more clever stuff than what we usually get out of this genre.
The 'five venoms' idea is the template for Tarantino's 'deadly viper assassins' from the "Kill Bill" volumes.