The Disaster Artist is a new film about the making of the worst movie ever: Batman v Superman.

Dubbed “the Citizen Kane of bad films”, The Room is a 2003 romantic drama produced, written, directed by and starring Tommy Wiseau, played here by James Franco who also directs. I’ve heard that he directed the film in character as Tommy, which explains why it’s badly directed. I wondered whether it was also written in character. Turns out it’s just by the writers of The Pink Panther 2.

Scott Neustadter and Michael H. Weber’s screenplay is based on the brilliant book The Disaster Artist by Greg Sestero who played Mark in The Room, but radically alters Greg’s character and his role in proceedings. In real life (assuming the book is factual), Greg took Tommy up on his offer of being a line producer on The Room, but refused to be in the film because he saw it for what it was: a hubristic, homoerotic and misogynistic mess. With Mark already cast and shooting underway, Tommy offered Greg a large sum of money and a new car to take the role, and Greg reluctantly accepted – and promptly grew a beard as a disguise to protect his acting career. Tommy then replaced the original actor without telling the guy.

In the film, Greg (Dave Franco) is just as delusional as Tommy, immediately accepting the role with complete confidence in Tommy and his vision. He only wants to keep the beard because it lands him a part in Malcolm in the Middle after randomly bumping into Bryan Cranston (Bryan Cranston). For some reason it’s important that he has the beard in Malcolm in the Middle, despite this being the most horribly fake-looking beard this side of Kill Bill Vol. 2. The reasons for this drastic change are twofold. Firstly, they wanted to shoehorn Bryan Cranston into the film. And secondly, they needed Greg and Tommy to be on the same page in order to make this a straightforward story about friendship; two buddies making their movie together.

I understand why you’d change the details of a true story in order to make a film more interesting, but this has the opposite effect, removing the story’s main source of tension. The Disaster Artist is a truly fascinating book, but not because of what it has to say about friendship. It’s a story of jealousy and manipulation, that manages to get under the skin of one of the most mysterious people in (or rather outside) the industry. Removing that friction takes away the strangest elements of the story, leaving a simplistic revisionist history that thinks it’s more important to have Bryan Cranston show up than to actually examine the thinking behind such a singularly bizarre attempt to make a normal American drama.

The Bryan Cranston cameo is indicative of an insular and incestuous project that’s completely at odds with the people at the heart of this story. Making Greg into a grinning imbecile allows them to cast James Franco’s brother Dave, as well as Dave Franco’s wife Alison Brie, their friend Seth Rogen and someone called Tom Franco although I’m sure that’s just a big old coincidence. Not only is this incestuous to the point of distraction, it’s also incongruous given the subject matter. Tommy Wiseau’s is the ultimate outsider’s story. So why have Bryan Cranston, Sharon Stone, J.J. Abrams, Adam Scott, Zac Efron and Judd Apatow show up with all the inconspicuousness of a man wearing two belts? Mind you, the most distracting piece of casting is actually Nathan Fielder, because the making of The Room feels oddly like an episode of Nathan For You (which happens to be the best thing on TV).

The Room is a genuine cult cinematic oddity and this feels like a cynical attempt by an obnoxious Hollywood clique to hijack it. Who is this film really about? It’s not about Tommy Wiseau on anything beyond the most superficial level, and it’s certainly not about Greg Sestero. It’s not about the fans, because why would they want to watch famous Hollywood insiders recreate their favourite scenes when they can see the real thing at midnight screenings throughout the year, with the real Greg and Tommy in attendance? No, this adaptation is all about James Franco and his friends. I’m fed up with this world.