The pertinent content causing the change in the ESRB rating involves more detailed depictions of blood and gore than were considered in the original rating of the game (the game already carried a Blood and Gore content descriptor), as well as the presence in the PC version of the game of a locked-out art file that, if accessed by using an apparently unauthorized third party tool, allows the user to play the game with topless versions of female characters. The locked-out topless skin was found by ESRB to exist in a fully rendered form on the game disc, but is not accessible in the Xbox 360 version of the game.
Rumors have emerged in the past few days that Oblivion has been pulled off the shelves of many retailers, which is now explained by the ESRB's action. According to the organization, developer Bethesda is contacting retailers to ensure that the game is not sold to consumers under the age of 17. Stores will also be required to rebrand existing packaging with "M (Mature)" stickers, which will be included on the packaging of further print runs. Bethesda is also working on a patch for the PC version of the game that will disable access to the offending art assets.
Coincidentally enough, Oblivion is co-published by Take-Two Interactive, parent company of Rockstar Games. Last year, Take-Two and Rockstar were blasted for similar hidden materials in Rockstar's Grand Theft Auto: San Andreas (PS2, Xbox, PC), in last year's "Hot Coffee" scandal. When accessed through a mod or a third party "cheat code" device, players were able to participate in a mini-game depicting sexual activity between consenting adults.
"This proactive move to change the rating once again confirms that ESRB's first priority is to ensure that consumers have reliable, accurate information with which to make educated decisions about the games they or their children play," said ESRB president Patricia Vance.
UPDATE: Bethesda Softworks has issued a press release responding to the ESRB's rating change on Oblivion. The response indicates that Bethesda will be acting in full compliance with the wishes of the ESRB on the matter, but is also firm in stating that Bethesda proceeded in good faith throughout all of its dealings with the ESRB in obtaining the original "T (Teen)" rating for the game. Bethesda reiterates that there is no nudity in Oblivion without players resorting to a third party modification, and the company is currently working to ensure that such tampering cannot occur in the future. The developer also maintains that it fully disclosed all violent content in the game during the ratings process, including indicating that the game has "frequent" blood and violence as well as "occasional torture, vulgar acts, and gore." Co-publisher does not expect the change to affect the success of the title, which has seen universal acclaim and strong sales figures since its release in March.