During an appearance on the Happy Sad Confused podcast to promote his new film, Here, Zemeckis was asked if there was anything that he'd like to tackle before he retires, such as a genre that he hadn't worked in before, or an actor that he hadn't worked with yet. The director responded by saying that he would like to produce Back to the Future: The Musical as a feature film, not unlike the filmed version of the Broadway production adapting Mel Brooks' The Producers.
The stage musical version of Back to the Future opened in London's West End in 2021 to rave reviews, receiving the Laurence Olivier Award for Best New Musical in 2022. The show moved to Broadway in August 2023, with a national touring production beginning in June of 2024. However, it doesn't look like the movie adaptation will happen, as Zemeckis has already pitched the idea at Universal and "they don't get it."
I generally don't like musicals except for Enchanted, which I attribute to Disney kind of making fun of itself. However I've never seen a proper stage musical and as BTTF is one of my favourite films ever, I went to see the musical earlier this year.
I can't deny I was really entertained all the way through but I had no idea there was going to be about five minutes of "normalcy" before another song kicks in. I think there's around 14 songs in total.
Part of the magic is what is achieved on stage for sequences like the DeLorean driving around trying to get up to speeds of 88mph. I feel some of that would be lost in a transition to film because, in a way, that already exists.