The 2025 edition of Off replaces the soundtrack from the original 2008 PC release with a new score due to the composer, Alias Conrad Coldwood, being reluctant to sign away the rights to his music. According to Toby Fox, one of the guest composers for the new score, Coldwood held no ill will towards the decision to replace his work, giving his approval towards the 2025 version's soundtrack.

Fox also stated that he was hesitant to contribute to the new soundtrack, comparing it to "breaking into somebody's house and pasting your face into their family photo album." Ultimately, he agreed to come on board after being directly asked by the game's creator Mortis Ghost. Fox stated that his most difficult contribution was the main battle theme, likening the assignment to "[taking] a bullet in the back for everybody else." He started by listening to several jazz recordings from the 1920's, and then commissioned frequent collaborator Carlos Eiene to record a "fake jazz song" in that style for him, which Fox then chopped and screwed into six different permutations. The first of these was then remixed several more times by frequent collaborator Masaya "Camellia" Oya, with each mix being intended for a different portion of the game.