The British experimental filmmaker Charlie Shackleton is probably best known stateside for his protest film Paint Drying. A ten hour and seven minute compilation of the very thing named on the tin, the film was initially made as a statement against censorship practices in the United Kingdom. But, since then, it has become a curio on the social media app Letterboxd, where users have used the film’s review page as a sort of community cork-board upon which to share their own traumas, life updates, calls to action, and much more. Paint Drying has, in other words, taken on an unexpected second life completely separate from its original intentions, yet still, in some way, perpetuating the very thing it was created for.

With Zodiac Killer Project, Shackleton has now taken one of his own works’ second life into his own hands. It is a documentary about his own shelved film, which was intended as a foray into the infamous Zodiac serial killer cold case. Instead, he’s created a reclamation project that, in its essayistic quality, becomes a criticism of the very genre that he had, at one point, wished to traffic in. In addition to his filmmaking and multimedia artistry, Shackleton is a film critic, and so Zodiac Killer Project becomes an inadvertent conglomerate of all the avenues of the artist’s interests.

Shackleton had planned on adapting The Zodiac Killer Cover-Up: The Silenced Badge by the highway patrolman-turned-amateur sleuth Lyndon E. Lafferty. The CHP officer had worked tirelessly following George Russell Tucker, whom he was convinced was behind the killings (a notion that was ultimately refused by the FBI). But, suddenly, Lafferty’s family withdrew the rights to the book, and Shackleton’s plans were thwarted. Like Jafar Panahi, whose This Is Not A Film imagines the movie he could’ve made were it not for the authoritarian crackdown in Iran, Shackleton’s work is a three-dimensional resurrection, a comment on the evolution of a genre, and a rueful rumination on artistic obsession.

The film follows a simple pattern. Over relatively static images of Vallejo, California and the surrounding areas that the Zodiac Killer mostly stalked, Shackleton maintains a consistent, florid voiceover in which he describes, in detail, what he had planned to do. The director’s voice is exceedingly warm, and he is beautifully well-spoken. His pontification of his own work as he describes what it could’ve been is the film’s starring attribute. Shackleton is often heard chuckling at the irony of the entire enterprise, in a way that refreshingly relishes its own absurdity, as he creates it, though sometimes the filmmaker might be too aware of his own cleverness.

Like Thom Andersen’s 2003 behemoth essay film Los Angeles Plays Itself, Shackleton tackles the endless barrage of tropes endemic to its subject.

The film’s target is the proliferation of true-crime documentaries and the inherent silliness of our consumption of it. Implicit to Zodiac Killer Project is a reflection of how all these itinerant texts have blended together to render an entire genre meaningless. Like Thom Andersen’s 2003 behemoth essay film Los Angeles Plays Itself, Shackleton tackles the endless barrage of tropes endemic to its subject. One of those many tropes is the predilection of filmmakers to frame characters and props in cross-section, a choice which Shackleton himself plays with in flashes of reenactment.

In this way, there is a funny solipsism to the work, whereby Shackleton (who also did the editing), plays in the sandbox he dismisses. Some of these tropes, it seems, are inevitable. In one section, Shackleton ponders the ethical standards which are glossed over in service of entertainment. “If you’re convinced it’s for the greater good, there are a very few ethical lines,” he suggests, “as far as HBO execs are concerned.” But Shackleton seems to wonder for himself if the work he’s put into this project can be justified, especially when the story has already been serviced, most notably by David Fincher with Zodiac. Is he just doing the same thing the creators of Making a Murderer did, in a reckless “slide into sensationalism” between its first and second seasons?

The film is immensely pleasurable to sit in. It’s impossible to know just how effective the original project would’ve been, but Shackleton has pulled off something possibly stronger, especially when he carefully draws a connection between himself and Lafferty. One especially searing moment comes when Shackleton tells the story of how the officer attempted, and failed, to procure Tucker’s fingerprints. The feeling of agonizing loss at what could’ve been is felt by both filmmaker and subject, across space and time, across genre and canvas.

Though the images here are relatively innocuous, there is something evocative about their placidity and the tension of what might happen inside the frame. Of course, nothing does. And yet, Shackleton makes us believe something still could. Like filmmaking itself, the excitement of what could be is often more thrilling than what is. Its a contradiction which keeps us returning both to the Zodiac case, and the movie theater. Instead of succumbing to the false posture of moral reckoning which pockmarks so many documentaries before it, Zodiac Killer Project delights in the confusion of the open question. Who cares if we don’t know who the killer was, or if the film gets made? Wondering is more exciting, anyway.