The game was originally designed as an episodic game when it was first revealed. Bandai Namco decided to cancel the Japanese console versions of Twin Mirror shortly after Dontnod acquired the IP rights from Bandai. As well as Shibuya Productions becoming a co-producer of the game. In June 2019, Dontnod announced to self-publish the game, with Bandai Namco Entertainment acting as the distributor for the console versions. The decision to set it in a fictional American town, based on southern West Virginia, was to broaden its appeal.

According to art director Pierre-Etienne Travers, the game's primary concept is duality. Д¬ontrary to previous titles, Dontnod desired to have Twin Mirror be void of any supernatural elements. Lead writer Matthew Ritter was influenced by adventure games like Beneath a Steel Sky and Space Quest. About forty people were working on it as of September 2018. Partnering with publisher Bandai Namco Entertainment Europe, Dontnod Entertainment began developing Twin Mirror in 2016 with a separate team of senior developers. Sam teams up with Anna, his ex-girlfriend who knew Nick well as they worked together in the Basswood Jungle, in hope that by following leads and investigating clues may lead to finding the source of Nick's death. The player can decide whether or not to look into the events resulting in Nick's death, but will ultimately be forced to investigate. During his stay in the town, Nick's daughter, Joan, asks him to check on the events leading up to Nick's death as she finds his activity before he died suspicious. He originally left Basswood due to an article he wrote about the coal mines which ultimately got them closed, leaving hundreds without jobs and angry townsfolk who all despise Sam. Samuel 'Muley' Higgs, formerly known as an investigative journalist, returns to Basswood, West Virginia in light of his close friend Nick's death.

Twin mirror length