Zone of the Enders entered development for the PlayStation and PC, but in actuality Konami had no intentions of releasing them for those platforms. The game's focus is on
anime-style robots with an emphasis on realism compared to common sci-fi works. Development staff were advised by professionals who had done scientific research for other anime series. Director and scenario writer Noriaki Okamura wanted to write a serious story featuring people with complicated lives; its main theme examines the purpose and nature of life, as reflected in Leo's hardships during the game. To support this message, multiple endings for the main narrative were avoided, although
side quests could feature different endings. Despite this, two other endings can be unlocked depending on the player's performance when protecting civilians. In contrast to other 3D games, the team worked to give players the sensation that they are controlling a fast robot; this demanded a year of camera work to achieve. Okamura designed
Zone of the Enders to tell a story through
gameplay sequences, rather than during
cutscenes. As such, the staff focused on adding details such as the destroyed buildings to inform the player's objectives. Character designer Nobuyoshi Nishimura expressed difficulties in designing characters who would both fit the mechas and the 3D models. In order to take advantage of the 3D space, Nishimura sought to move the camera as often as possible. He tried not to "go overboard" during cutscenes to emphasize the appeal of the mechas during gameplay. During development of the game, producer
Hideo Kojima assisted the team. As a joke, Shinkawa placed the cockpit in the Frames' crotch region. The staff first had the idea of naming a Frame
Anubis based on
Egyptian mythology; this led to the name Jehuty for the main Frame, a reference to the Egyptian deity,
Djehuti. LEVs were intended to appear during the gameplay as weak, easy opponents that would target Jehuty and the Raptors; however, they ultimately appeared only during cutscenes.
Zone of the Enders was originally set to release in Japan on February 1, 2001, but was delayed to March 1, 2001. The Japanese edition premium package contains an
original video animation titled
ZOE: 2167 IDOLO; produced by
Sunrise, it is set five years before the events on the game. Okamura was satisfied with Sunrise's work, noting their experience in producing robot anime. They were originally sold packaged with a preview demo of the then-upcoming
Metal Gear Solid 2: Sons of Liberty. The game's soundtrack was released in Japan on April 25, 2001 by
Konami Music Entertainment. According to director Okamura, the music is calm during normal situations, with new tracks added in combat situations to increase the complexity of the music while fighting. The main theme, "Kiss Me Sunlights", was composed and performed by Heart of Air. ==Reception==