Beijing is extremely sensitive to even subtle hints of dissent, and in 2020 imposed a national security law in Hong Kong that has effectively quashed any political opposition.

In "Reversed Front: Bonfire", developed by a Taiwan-based company, users can "pledge allegiance" to entities including Taiwan, Hong Kong, Tibet and "Uyghur" to "overthrow the communist regime".

Although the game takes place in a historically different universe, the description reads: "This game is a work of NON-FICTION. Any similarity to actual agencies, policies or ethnic groups of the PRC (People's Republic of China) in this game is INTENTIONAL."

On Tuesday police said "Reversed Front" was "advocating armed revolution" and promoting Taiwan and Hong Kong independence "under the guise of a game".

Downloading the game could see players charged with possessing seditious material, while making in-app purchases could be viewed as providing funding to the developer "for the commission of secession or subversion".

Recommending the game could constitute the offence of "incitement to secession".

Although players can choose to "lead the Communists to defeat all enemies", the game description makes clear they are meant to be the villains.

The Communists are described as "heavy-handed, reckless and inept" and accused of "widespread corruption, embezzlement, exploitation, slaughter and defilement".

Many of the other playing roles correspond to flashpoint issues for Beijing -- including self-ruled Taiwan, which China claims as its territory, and Xinjiang, where it has denied accusations of human rights abuses against the minority Muslim Uyghurs.

Hong Kong's vibrant civil society and political opposition have all but vanished since the imposition of the national security law, which was brought in after huge and sometimes violent pro-democracy protests in 2019.

On Wednesday Apple appeared to have removed the game from the Hong Kong version of the App Store, after it had been available the day before, an AFP reporter saw.

It was not available on Hong Kong's Google Play on Tuesday, local media reported.

But the game's developer said it had seen a surge in searches since Tuesday's police announcement, jokingly implying it was thankful to authorities for the visibility boost.