With a fake release date of 31 October, Brexit Royal imagined an apocalyptic post-Brexit world where all UK trade links are cut off and its borders closed.
Players would have to fight against each other to stockpile food supplies and battle to the death, using weapons that included a blue passport, ballot boxes and a wheat-firing crossbow.
The aim of the stunt was to start a discussion on the reactionary and often hysterical negativity surrounding gaming in the mainstream media.
Several tabloids called the game 'a sickening incitement of violence against MPs'.
As well as the national media coverage, the campaign achieved more than 12 million impressions as #BrexitRoyal trended on Twitter, plus tens of thousands of engagements and views of the teaser trailer.
Kairos Group is a global network of agencies that includes influencer marketing and creative agency Kairos Media, specialist gaming and e-sport consultancy Kairos Esports, and media owner Kyma Media.
Director and head of client services, Luke Bristow, said: "Anyone looking at the game could tell that it’s a light-hearted joke not to be taken seriously, but the hysterical pick-up it got proved our point perfectly."
Co-founder Mike Craddock added: "A stunt such as this was the perfect way to show the access we have to engaged users and the sheer reach of our channels."