Development of Resident Evil: Operation Raccoon City started in early-to-mid-2010, and information on "Resident Evil: Raccoon City" was leaked to Kotaku in October, though Slant Six refused to confirm its new project outside of working with a "new publishing partner on a world class franchise".
Though Slant Six's production staff had hopes of developing a game more in keeping with older Resident Evil titles, Capcom instead wanted a game more akin to their SOCOM series. When the game was announced officially in late March 2011 the final concept was more clearly demonstrated, along with a new cast of USS characters in futuristic uniforms. The characters of VECTOR; SPECTRE; BELTWAY and BERTHA were announced, and magazines showcased their designs. At this time Capcom producer Masachika Kawata had estimated in a 1UP interview that the game was approximately 45% complete. At E3 2011 the characters of LUPO and FOUR EYES were introduced by Capcom Unity, and Kawata announced that development of new enemies was ongoing.
Later in development, Slant Six began development of a second campaign mode where the playable characters would consist of soldiers in a US Army unit dubbed "Echo Six". Unlike the "Wolfpack" campaign, which was to revolve around destroying incriminating evidence and silencing witnesses, especially Leon S. Kennedy, the Echo Six missions were to involve the US Army attempt to rescue civilians and find the truth behind the outbreak. This campaign was largely an afterthought, and its storyline did not link up with the Wolfpack's, effectively creating two "what if" scenarios. The first mission of this campaign was released as free DLC in April 2012.
In January 2012, shortly before release, four multiplayer modes were announced, which put players against one another in a Zombie-infested environment. "Team Attack"; "Survivors"; "Biohazard" and "Heroes" were to be available for all consoles, with the latter being a team game consisting of established characters. A fifth mode, "Nemesis Mode", was announced as an Xbox 360-exclusive, and put two teams against one another with the objective of activating the Nemesis T-02 to destroy the opponents.
In the final product, a lot of the weapons had design changes from the real life based models. The differences can be seen in the Kendo Gunshop catalog from Inserted Evil.
The soundtrack to Operation Raccoon City is set to be released on May 16, 2012 alongside the Japanese edition of the game. Nevertheless, gamers have managed to rip music files for YouTube audiences, much like Revelations was earlier in the year.
Capcom has announced that Resident Evil: Operation Raccoon City's soundtrack will feature an exclusive theme song in Japan - No Escape by Coldrain which is going to be released as a single on April 20.