With a satisfying protagonist completed, Sega turned to programmer Yuji Naka, who had impressed them through his work on "Phantasy Star" and the Genesis port of "Ghouls 'n Ghosts". Naka was a fan of "Super Mario Bros." but desired something faster, so the game was made to play quickly, which was where he focused most of his effort. Naka explained that the reason he wanted a fast game was that he had ported "Ghouls 'n Ghosts", and wanted to work on its movement but found it slow.