It's a bit confusing. The Donkey Kong Land series are entirely new games. The first game tries a bit
too hard to be as good looking as DKC, but the second and third games are more mindful of the system's screen and are absolutely worth your time.
There was also a port of DKC to the GBC. It's fantastic that they actually got the game working at all, but
it didn't exactly fare very well, and the GBC's screen didn't help matters. It was basically a tiny blurry mess of browns. The GBA ports are much more serviceable ports, if you don't want to play the SNES versions on a 3DS for some reason.