Baby Driver would be a fine action/heist movie if it was just that, but Baby’s music-driven existence gives the film an immediate and clever hook. With virtually every scene set to our hero’s eclectic soundtrack of oldies, indies, and everything in-between, the film becomes a musical. No one breaks into song, but they might as well. The rhythm of machine gun fire aligns with the beat of the soundtrack. Cups of coffee placed on a table act as a percussion back-up to the song blasting through the speakers. A walk through the city streets becomes a full-blown musical number that only we can notice, as the mundane choreography of day-to-day living syncs up with the music playing in Baby’s ears.
Spielberg, who felt that the characters in Benchley's script were still unlikable, invited the young screenwriter John Byrum to do a rewrite, but he declined the offer.  Columbo creators William Link and Richard Levinson also declined Spielberg's invitation.  Tony and Pulitzer Prize –winning playwright Howard Sackler was in Los Angeles when the filmmakers began looking for another writer and offered to do an uncredited rewrite; since the producers and Spielberg were unhappy with Benchley's drafts, they quickly agreed.  At the suggestion of Spielberg, Brody's characterization made him afraid of water, "coming from an urban jungle to find something more terrifying off this placid island near Massachusetts."