Rees specifically wanted characters to be able to break out into song whenever they wanted to, similar to the films of the Hollywood Golden Age. Once they were written, Newman used the songs in his own score. For example, the first song in the film, "City of Light", displays the character's naivety and apprehension, and contains a motif that gets more complex as the film goes on. This approach made the score more cohesive. "It's a B-Movie" is filled with black humour and an ominous pipe organ as the mutant appliances scare the main characters. The synthesizer-driven "Cutting Edge" sees the Master's state-of-the-art appliances boast about how great they are. The poignant number "Worthless" is a track filled with piano, strings, guitar, and vocals which are abruptly cut off when the singing cars are crushed. The junkyard sequence's climax evokes feelings of desperation, danger, suspense and real world peril. Newman "reprises the score's subtle and varied themes over the end credits". Newman wrote and orchestrated the score over a 50-hour period, which included embarking on a 12-hour flight to Japan to record with the orchestra in Maeda Hall.