Recently I had the dubious honour of watching Late Shift, which bills itself as “the world’s first cinematic interactive movie.” As the movie unfolds, the cinema audience decides—using a smartphone app—how the protagonist responds to various situations, affecting how the story plays out on the big screen. There are about 180 different decision points that produce both big and small storyline branches, with seven different endings in total. The movie is being released at Vue cinemas in the UK in March 2017.

The actual running time of the movie is about 90 minutes, depending on the decisions you make, but the total amount of film, including all the endings and branches that you don’t get to see, is about four hours. When I watched Late Shift, the audience’s decisions led to an extremely quick and brutal ending; later, the UK distributor of the movie told me that, if we’d made another choice, the movie could’ve run for another 20 minutes.