A 2’9” footnote in cinematic history is investigated to surprisingly rewarding ends in “The Search for Weng Weng.” Andrew Leavold’s documentary pokes at the puzzle of a long-neglected novelty Filipino movie star, gaining insights into not just his forgotten subject’s ill-chronicled life, but also the nation’s “Second Golden Age” of cinema in general. It’s a winding, digressive road that eventually leads to the door of Imelda Marcos herself. This entertaining, good-humored yet respectful homage to a unique exploitation-film figure has been picking up fans on the festival circuit for some time (beginning in 2007 as a work-in-progress), and could parlay that attention into some limited theatrical exposure. Wider but still niche home-format sales are assured.

Australian helmer Leavold first became a Weng Weng enthusiast as owner of his country’s cult video store, Trash Video, whose stock included what appeared to be the star’s only vehicles: the 1981 spy spoof “For Y’ur Height Only” and “The Impossible Kid.” Both were antic, high-energy cheapies distinguished by deliberately ridiculous dubbed English dialogue (recalling Woody Allen’s “What’s Up, Tiger Lily?”) and the conspicuous presence of diminutive Weng Weng (named after a potent local fruity cocktail) as their unlikely karate-chopping, babe-magnetizing superspy.

But intel on this shadowy figure was impossible to find. The documentary begins with Leavold querying a presumably knowledgable Cinemanila Film Festival audience, only to get responses divided between the bewildered and offended. Those who do remember the tiny phenomenon’s movies now consider them embarrassing mementoes of a pre-modern cinema in which the nation’s traditional “fascination with the macabre” could be indulged by treating “a handicapped person” as court jester. No one seems to have the slightest idea about Weng Weng’s background, let alone what became of him.

Nonetheless, Leavold perseveres, eventually stumbling upon an old-boy network of surviving if now underemployed players in the flourishing Pinoy action movie industry of several decades ago, including directors, editors, stuntmen and co-stars. He finds out soon enough that Weng Weng (born Ernesto de la Cruz) died years earlier, amid the same slum poverty he’d been too briefly plucked from. Less expectedly, perhaps, he learns there were at least a dozen films featuring the performer, going back as far as 1976. Many are excerpted here, though given the erratic-at-best state of film preservation in the Philippines, others may have disappeared for good.

Former co-workers and acquaintances attest to the star’s affability, childlike innocence and openness to anything, including doing his own often risky stunts. But some also saw him as a sad, overly trusting figure who was taken advantage of, most notably by a husband-and-wife producing team who simply dropped him back into the obscurity he came from when they left movies for a new career in politics. Weng Weng’s vehicles were popular — “Height,” in particular, sold to numerous foreign territories — yet by all accounts he was never paid a salary, let alone given a profit percentage. Instead, he was kept as a sort of indulged pet, then discarded. While living the high life, he was apparently a frequent guest at the presidential manse, as remembered here by both Imee Marcos (who headed her father Ferdinand’s film commission) and, eventually, by Imelda herself in a surreal visit to the erstwhile uncrowned empress’ plush current digs.

While sussing out its titular mystery, “The Search for Weng Weng” provides a good sketch of the period’s wildly prolific film industry — one thing, it’s pointed out, that flourished under the Marcoses’ otherwise highly questionable martial-law regime. (The documentary’s perspective on that era is more insightfully insiderish than that of Mark Hartley’s 2010 “Machete Maidens Unleashed!,” which also spotlit Weng Weng and had Leavold as an associate producer, but focused primarily on international co-productions.) Back then, almost 300 features were released per year, several times the number produced today. Their disposability only heightens the nostalgic affection that onetime industry participants hold for them, not to mention psychotronic-cinema fans like Leavold. By the pic’s (admittedly attenuated) end, the director has managed to create a groundswell of new cultdom for his deceased subject.

Though the final flurry of “We Heart Weng Weng” sentiments (as well as the input from one particularly grating Pinoy film academic) pushes the “too much of a good thing” envelope, for the most part “Search” is delightful and unexpectedly deep. Production resources clearly weren’t abundant, but the package is well turned nonetheless.