While London retains a monarch, a parliament, and a mayor, the true power lies with the Masters of the Bazaar—cloaked inhuman beings who oversee domains of trade and enact mysterious agendas.

While the industry, poverty, and high-class society of Victorian London remain, its strict social mores have been disrupted by strange new factions roaming its streets.

Across the vast ocean of the Unterzee lies the Khanate empire, the impenetrable Elder Continent, and the screaming island of Polythreme, which exports clay labour to London.

Those who succumb to nightmares and madness are welcomed to the Royal Bethlehem hotel or slip into a dream-realm, Parabola, which is closer to London than to surface locations and is sometimes visible through mirrors.

They have no living expenses, and though players may choose a profession for a periodic income, they can publish a newspaper, serve out repeated prison sentences and feed deliverymen to a man-eating plant without harming their job security.

Four of these are the character's main attributes (Watchful, Shadowy, Dangerous, Persuasive) which are constantly used for succeeding in actions, though failure may also increase the corresponding menace (Nightmares, Suspicion, Wounds, Scandal).

[3] Alexis Kennedy began solo development of Fallen London as an amateur project in June 2009, creating the setting, building the site and writing the initial content.

He had originally intended the game to be an entirely text-based experience, but quickly realised that art would enhance the project, and recruited a friend, Paul Arendt.

[10] Rock, Paper, Shotgun's Adam Smith wrote in favour of its writing style along with its "inventive setting", "dripping with lore".

[12] Alana Joli Abbott for Black Gate also reviewed Fallen London and said "I do enjoy dabbling in the game, and I suspect that eventually, I will attain that enviable rank of Person of Some Importance.

[19] The Silver Tree is also a browser-based choose-your-own-adventure game, but occurs roughly five hundred years before the time of Fallen London and focuses on the events surrounding the fall of the Fourth City, Karakorum, capital of the Mongol Empire.

[21] In 2023, Failbetter released a romantic visual novel set in the Fallen London universe called Mask of the Rose, which serves as a prequel to the other games in the franchise.