The Chaotix, who had appeared in the 1995 spinoff game "Knuckles' Chaotix", were revived for "Sonic Heroes" because Sonic Team thought they were unique and had never used them. Iizuka said he did not consider the Chaotix in "Sonic Heroes" the same team from "Knuckles' Chaotix", claiming to have created new characters using the same designs from 1995. The game marks the debut of E-123 Omega in the "Sonic" series. Sonic Team wanted to include as many teams as possible, but time constraints and a desire to keep the gameplay balanced prevented this. The game features several computer animated cutscenes produced by Vision Scape Interactive. Jun Senoue composed the majority of the soundtrack. His band Crush 40 performed the main theme, "Sonic Heroes", and the final boss theme, "What I'm Made Of". Other songs were performed by Ted Poley, Tony Harnell, Kay Hanley, Julien-K, and Gunnar Nelson. Iizuka said that the intention was for the music "to return to the roots of the "Sonic" experience" and be exciting and fast-paced.