Banjo-Kazooie creator reveals that the mythical "Stop 'N' Swop" feature was originally bigger than we ever knew, with Donkey Kong 64 being a planned part of the process

Banjo-Kazooie director and long-time Rare staffer Gregg Mayles has revealed the original design document for the mythical Stop 'N' Swop system, revealing that Donkey Kong was also involved in the process.

Mayles, who left Rare earlier this year following the cancellation of Everwild (which in itself was a part of Microsoft's sweeping layoffs), posted a document on Twitter (spotted by DK Vine) revealing plans for the "Coldswap" mechanic, which was known as the Stop 'N' Swop in Banjo-Kazooie. Not only did these documents reveal that Donkey Kong 64 was also going to be part of the process but that Donkey Kong would become an unlockable character in Banjo-Tooie's multiplayer mode at the end of it.

Stop 'N' Swop – for those unaware – was a proposed feature included in the original Banjo-Kazooie, where players would collect eggs and an Ice Key with the promise of them unlocking something in Banjo-Tooie when it eventually released, which would be done by physically swapping out the cartridges while the N64 is running.

However, Tooie was released without the feature, turning it into an urban legend for years, until the Xbox 360 ports of the game reintroduced the feature, rewarding players with the likes of Avatar images and content in Banjo-Kazooie: Nuts & Bolts. The reason this was never implemented was apparently due to an N64 hardware revision where the game was stored in the consoles' RAM for 10 seconds, giving players a while to swap it over, but the new consoles reduced it to one second.

Previously it wasn't known that Donkey Kong 64 would be a piece of the puzzle, but Mayles' documents lay out how players would transfer items from Banjo-Kazooie, through DK64, into Banjo-Tooie and potentially even further through something known as "Next N64 Game" (which Mayles says wasn't about anything in specific). The Stop 'N' Swop was already one of gaming's biggest "what if" moments, so to hear it was potentially far bigger than we ever knew only makes me think more of what could have been.

Before Banjo-Kazooie's mascot was a bear and after he was a human, the N64 icon was actually a rabbit, according to a former Rare developer