Development
Digital Devil Story: Megami Tensei was adapted from Digital Devil Story, a trilogy of science fiction books written by Japanese author Aya Nishitani. Published by Tokuma Shoten, the novels were a major success in Japan. Nishitani and Tokuma Shoten began working to adapt the books into a multimedia series, beginning with an original video animation (OVA), which retold the events of the first novel, and creating a tie-in video game during the OVA's production. Initially pitched to Nintendo and turned down due to the book's mature elements, the game license was pitched to other publishers. The license to develop a game based on Nishitani's work was simultaneously acquired by two companies; Atlus who applied through Namco, and Telenet Japan. The two companies were willing to work on the same project, but wanted to differentiate their products. As the Famicom was noted for action-based titles and PCs for traditional role-playing games, the two companies decided to respectively play against platform expectations. Two different game projects were created with Tokuma Shoten's supervision under the Digital Devil Story: Megami Tensei title; Atlus created a traditional role-playing game which was published by Namco, while Telenet created (with assistance from Atlus) an action role-playing game, which it self-published. The two versions were developed concurrently, although the version by Telenet was the first to be completed.
The Atlus version was directed by Kouji Okada, while the scenario's original elements were written by Kazunari Suzuki. Sprite and promotional artwork was designed by Esaki Minoru, and the music was composed by Tsukasa Masuko. During the early phases, the gameplay concept was a near-copy of the gameplay style of the Wizardry series, attributed by Suzuki to their superiors being fans of the series. Suzuki insisted on the inclusion of some new feature which would distinguish it from Wizardry. This resulted in the creation of the demon negotiation system. Okada later stated that demon negotiation was decided upon from an early stage. Speaking later about the first-person exploration, Okada was highly critical, feeling that after all their efforts "All we had left after everything was said and done were lots and lots of long, winding dungeons!". Storage space on the cartridge was a recurring concern for the team, with Suzuki using unspecified programming tricks to include high-quality sprite graphics. Due to the rules of the gaming industry at the time, the teams and studios either went uncredited or had pseudonyms, with Masuko being credited as "Project Satan".
Nishitani was deeply involved in planning the game, contributing suggestions and advice for the project. According to Okada, a major issue during development was faithfully following the novel's plot due to the limited hardware space on the Famicom cartridge, together with the necessity of creating a compelling gameplay experience. With this in mind, the team picked out key parts the novel's plot to include in the game while cutting out non-essential elements. One element that was not included was the questionable morality of the main protagonist, which was a prominent feature in the novels. These cuts and changes were made with Nishitani's permission, which Okada attributed to the Telenet version already closely following the novel, giving Atlus more creative freedom. Suzuki later commented that it was only because they were working with Namco that the game was ever released, due to its mature character designs and heavy use of religion in the narrative. The Cerberus demon, which would become a recurring feature in later Megami Tensei games, was a homage to the narrative of Nishitani's trilogy, at the same time emulating the trend for games to have a marketable mascot or character.
