Until late 2003 Resident Evil 4 was in its "Hallucination" stage of development, which featured Leon S. Kennedy exploring the Spencer Estate and suffering halluncinations from a Progenitor Virus infection. The GameCube was found to be unable to load the two simultaneous versions of each room necessary for Leon's hallucinations, and the game was scrapped. This also prompted the departure of Yasuhisa Kawamura and Noboru Sugimura as writers, their last completed script having been already rejected and turned into the game Haunting Ground.
"Zombie" was seen by staff members as a return to the franchise's standard formula, which producer Shinji Mikami had become highly-critical of for boring established fans with repetition. Little information is known of the intended setting of this game, as no concept art is known to have been made. What is known is that there was to be a new type of human enemy, referred to as dabamen (ダバメン?). Soon after the project began, producer Shinji Mikami dismissed Shibata and took over directoral duties, ending the "Zombie" project. The Dabamen were later recycled as the Ganados .