Although visually similar to Rare's previous games, such as Donkey Kong 64 and Banjo-Kazooie, Conker's Bad Fur Day was designed for mature audiences and features graphic violence, alcohol and tobacco use, profanity, vulgar humour, fourth wall breaks and pop culture references. Development lasted four years, with concepts originating during the development of Killer Instinct Gold in 1996. The game, intended for a family audience, was initially titled Twelve Tales: Conker 64 and was set for release in late 1998, but by the time it received criticism for its kid-friendly tone and resemblance to Banjo-Kazooie during E3 1998, the game was transformed into an adult-oriented version of that product.
