Donkey Kong Jr. is a 1982 arcade-style platform video game by Nintendo. It first appeared in arcades, and, over the course of the 1980s, was later released for a variety of platforms, most notably the Nintendo Entertainment System.

Donkey Kong Jr. is known to be Donkey Kong Sr.'s son. He has not been in many games so far. His first appearance was in the game Donkey Kong Jr., where he makes his own task to rescue his father from Mario. He is implied to be the father of the current Donkey Kong.

Here it is on the Colecovision:

I couldn't find an online version to play so here is the original Donkey Kong!
https://archive.org/details/msdos_Donkey_Kong_1983