"Animal Crossing: New Horizons" is Nintendo's latest smash-hit success for its latest console, the Nintendo Switch.

Though the game isn't officially approved for sale in China, people have been able to buy the game through importers and by changing their console's region setting. "The game has become extremely popular in China," Niko Partners senior analyst Daniel Ahmad said of the news. "Even places like the Shanghai Fire dept used ['Animal Crossing'] to create some in-game messages."

But the Chinese government is cracking down on the game, and it looks like censorship may be to blame: Some players involved in the Hong Kong protest movement have shared images from the game, like the one above, voicing opposition to Chinese government policies.

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"Animal Crossing: New Horizons" is a massive hit, and the latest blockbuster for Nintendo's wildly popular Switch console.

It's popular all over the world, even in places where it hasn't officially been released — like China, for instance, where some users are using their "Animal Crossing" island to protest government policies.

Joshua Wong, a Hong Kong-based activist, offered one example on Twitter earlier this month:

—Joshua Wong 黃之鋒 😷 (@joshuawongcf) April 2, 2020

Because "Animal Crossing: New Horizons" has a feature that enables players to create their own designs, people can decorate their islands however they please — including with protest slogans.

Between user-generated content and the game's massive popularity, red flags within the Chinese government appear to have been raised: Sellers on Chinese re-selling marketplace Taobao have been banned from selling the game as of this week.

The ban comes directly from Chinese regulators, who cited an old policy that's rarely enforced, according to Niko Partners senior analyst Daniel Ahmad, who covers the gaming industry in China.

Games that do get hit with bans "usually fall under two criteria," Ahmad said. "The game has content or user generated content that is deemed to be too offensive or violent," or, "The game has become very popular and caught the attention of regulators."

"Grand Theft Auto 5" is cited as an example as the kind of game that might get flagged by Chinese government regulators. Rockstar Games

In the case of "Animal Crossing: New Horizons," the game fits both criteria.

"The game has become extremely popular in China," Ahmad said. "Even places like the Shanghai Fire Dept. used ['Animal Crossing'] to create some in game messages."

Notably, the game isn't officially approved for sale in China.

The Nintendo Switch was only recently approved for sale by the Chinese government, and a limited trio of games were approved for sale alongside it: "New Super Mario Bros. U," "Super Mario Odyssey," and "Mario Kart 8 Deluxe." But Chinese Switch owners are apparently able to skirt those restrictions pretty easily.

"The imported version of 'Animal Crossing' is basically just the [Japanese] or [North American] or [European] version imported into China," Ahmad said. Moreover, the game can be purchased by simply changing the region of your Nintendo Switch to reflect a region where the game is available.

Still, the game's ban on Taobao is notable — it is the "main platform" for buying imported versions of games in China that are otherwise not approved for sale. It's unclear if Nintendo intends to bring "Animal Crossing: New Horizons" to China at some point in the future, and Nintendo representatives didn't respond to a request for comment as of publishing.