I remember when I was younger, I found a hidden version of the original Donkey Kong game in Donkey Kong 64. I had never played it, and despite it being rather basic, I liked it and found it fairly fun to play. Once Mario is finished with New Donk City in Super Mario Odyssey, Mayor Pauline gives Mario a celebration. However he must go through a Donkey Kong level to get there.
While the beams and barrels are just like the original Donkey Kong, Mario moves more like he does in Super Mario Bros., just like the rest of 2D mini-levels in the game.
Big ol' bad Donkey Kong waits for you at the end. While the level isn't challenging, I found it to be a pretty neat homage.