This page explains in detail the interactions between the Donkey Kong series and the Killer Instinct (Rare) series.
Donkey Kong Country 2: Diddy's Kong Quest[]
November 20, 1995
Donkey Kong
Killer Instinct (Rare)
Cranky Kong's "Monkey Museum" features many items referencing Nintendo and Rare, the two companies that created the game, such as the companies' logos, but there also are references to Killer Instinct. Specifically, behind Cranky there's an arcade cabinet for the game, while on the wall there's a poster featuring an image of Chief Thunder, a fighter from the game. This poster is actually based on an alternate artwork of him, that only appeared on magazines and promotional material, not his main artwork used as his avatar. Additionally, Cranky's cabin is represented on the map of the Krazy Kremland area as a tent with a neon sign reading "KI here", and has two Killer Instinct cabinets outside.
License[]
While published by Nintendo, Donkey Kong Country 2 was produced by Rare, so they could freely include references to their own series.