Though Sleepwalker was released in collaboration with Comic Relief, it was not originally intended as a tie-in with the charity. Rather, when Comic Relief approached Ocean about making a charity game, it was too close to the date of the Red Nose Day telethon for a quality game to be made in time. Comic Relief were instead given a selection from Ocean's development lineup to choose from, and decided on Sleepwalker due to its comedic animations and plot. Comic Relief contributed the design for the bonus stages and allowed them to get British comedian and Comic Relief co-founder Lenny Henry as the voice of Ralph the Dog.