On the charcter select screen (the bar), you can see Banjo's severed and stuffed head mounted above the fireplace and if you look in the closet you'll find Kazooie's stuffed head being used as an umbrella handle.

Conker's Bad Fur Day started out as a much tamer game called Twelve Tales: Conker 64. Around the time of its announcement, Rare had already made two similar games, Banjo-Kazooie and Diddy Kong Racing. They feared criticism for making another innocent platformer starring "cutesy" animals, prompting them to completely redesign the game for older audiences in 1999. Rare kept it under wraps after this announcement, but assured it was still in development until the revamp was formally revealed in 2000.

In the original game, if you stand idle for a while, Conker will get out his Game Boy and play it. You don't get to play with it, but you can hear him playing Killer Instinct, another game made by Rare. In the game's remake, the console is replaced by a handheld console resembling the Game Boy Advance SP, where he can again be heard playing Killer Instinct. This idle animation was disabled in the Rare Replay release of the original game in 2015.

Chris Seavor voiced all of the male characters in the game besides The Great Mighty Poo.