Featuring insights from director Darren Lynn Bousman and cast members, Repo! This Movie: The Anatomy of a Cult takes a look at how the dark, cybergoth rock opera Repo! The Genetic Opera transformed from a small theatrical show to a modern day cult classic.

Here’s the thing: even though Repo! This Movie is ostensibly a bonus feature on the recent Lionsgate Limited 4K steelbook release of Repo! The Genetic Opera, it ought to be considered the main reason to pick up the release at all—yes, even more so than the remaster of the film itself. It’s one part behind-the-scenes look at the entire history of Repo! The Genetic Opera, from its earliest days as a small theatre show to its long-lasting legacy as a cult favorite, and one part celebration of the act of making a film that’s most decidedly out of the mainstream. The whole thing’s a bit like the recent Rocky Horror documentary, Strange Journey (whose director, Linus O’Brien, even makes a brief appearance), in the way that it balances the history of the film’s creation with an exploration of the film’s impact. So, if you’ve seen that film, you’ve got a good idea of what to expect here.

Longtime Repo! fans will delight at the absolute wealth of behind-the-scenes footage on display, all sourced from unearthed tapes recorded by Bousman’s then-girlfriend/now-wife during the production of the film. Her footage provides a raw look at the ups and downs of making Repo!, and it’s such a treat to be able to go into the recording studio with the cast and onto the set to watch everyone put this weird little film together. There’s particular joy in seeing the late Anthony Head and Paul Sorvino, each incredibly well-known stars who did not have to do a film like this, really giving their all to the film as if they’d been part of Repo!’s history from the beginning.

Most impressive of all, though, is how honest a documentary this is. It’s not one of those fluffy backstage pieces that tries to paint the whole production as all sunshine and roses. No, you can feel the bitterness that Bousman and co-creators Terrance Zdunich and Darren Smith have for some of the studio heads and media people who just didn’t get the project. And they’re all quite honest about the challenges of filming the piece, with its limited budget and tight schedule. But their joy for the piece, and the joy they’ve found seeing it resonate with fans and shadowcasts nearly 20 years after the film’s release, offer a testament to the sheer power of art.

As a documentary, Repo! This Movie occasionally feels a bit listless, particularly in its final third when it shifts its focus from the making of the film toward exploring the fandom that’s cropped up around the film over the last 17 years. But at its core, it’s never anything less than a loving and captivating glimpse behind the scenes of a film that’s unlike many others. Running a full thirty minutes longer than the film it’s documenting, Repo! This Movie offers a fascinating insight into the making of a modern cult favorite and is a must-watch for all fans old and new alike.

4 out of 5 wands.

Repo! This Movie is available exclusively on the new 4K Steelbook of Repo! The Genetic Opera, available from Lionsgate Limited.