Development of Resident Evil 2 began one month after the completion of its predecessor in early 1996.[35] The game was officially announced when the first footage was shown at the V Jump Festival '96 in July.[36] This early build, later dubbed "Resident Evil 1.5" ("Biohazard 1.5") by producer Shinji Mikami, differed drastically from the released version in its scenario, presentation and gameplay mechanics.[37][38] Its plot followed the same basic outline as that of Resident Evil 2, and featured a zombie outbreak in Raccoon City two months after the events of the first game. In this version of the story, however, Umbrella had already been closed down as a consequence of their illegal experiments.[39] The development team sought to retain the level of fear from the original game, and thus introduced to the narrative two new characters who lacked experience with terrifying situations: Leon S. Kennedy, largely identical to his persona in the final build, and Elza Walker, a college student and motorcycle racer vacationing in Raccoon City, her hometown.[38][39][40][41] Unlike the final version, the story paths of Leon and Elza did not cross, and each playable character had two support partners instead of just one.[40] Leon received help from fellow police officer Marvin Branagh and a researcher named Linda – an early version of Ada – while Elza was aided by Sherry Birkin and a man named John, who appeared in Resident Evil 2 as gun shop owner Robert Kendo.[40][42]
Real-world influences had an impact on several character designs by artists Isao Ohishi and Ryoji Shimogama. For example, Ohishi based Leon on his bloodhound, and Annette Birkin was modeled after actress Jodie Foster.[42] The police department in which Resident Evil 1.5 began had a more modern and realistic design, and was smaller than the final building seen in Resident Evil 2.[39][40] There were more encounters with surviving policemen, such as a superior officer of Leon called Roy.[40][42] The number of polygons used for enemy models was far lower than in the released version.[37] This allowed many zombies to appear on the screen, a method of invoking fear in the player that recurred throughout Resident Evil 1.5.[37][38] Furthermore, the game employed dynamic music, and frequently applied alterations to the pre-rendered backgrounds in response to events during the gameplay.[39] The playable characters could be equipped with gear, such as protective clothes that enhanced their defense and enabled them to carry more items.[43][44] The characters' polygonal models were altered by costume changes and by damage received from enemies.