The new guidelines came after Biden made an island promoting his campaign in the game's virtual world.
"Please refrain from using the Game inappropriately or creating any content within the Game that would be considered vulgar, discriminatory, or offensive. Please also refrain from bringing politics into the Game," the guidelines read.
Less than a month before the election, The Verge reported that the Biden campaign had created its own island, dubbed "Biden HQ," in the game -- replete with avatars of the former vice president and his running mate, Sen. Kamala Harris, D-Calif.
It reportedly included a field office and "train town" for Biden's favorite mode of transportation. In addition to campaign flyers and a flag with the "Team Joe" logo, it also included an apparent polling station with a "massive ad for the Democratic Natonal Committee's 'I Will Vote' website," The Verge noted.
“The island includes plenty of ice cream, trains, aviators, chucks, swag, and more weaved throughout the entire island — but there are also features that encourage players to organize and mobilize,” Christian Tom, who served as director of the campaign's digital partnerships, reportedly said.
The campaign previously released yard signs with four designs for players to download that they can place around their virtual island homes -- including the official Biden-Harris logo, the Team Joe logo, the “Joe” Pride logo, and an image of aviator sunglasses shaded in red, white, and blue.
Rep. Alexandria Ocasio-Cortez, D-N.Y., also started playing the game in May when she asked Twitter followers to send her their "dodo codes." She apparently went on to visit other gamers' islands while wearing a shirt that read "AOC." It's unclear how much she's played since then.