This is a tool-assisted speedrun. For more information, see http://tasvideos.org/3789M.html. TAS originally published on 2018-09-17.
While the NES versions of Donkey Kong, Donkey Kong Jr., Donkey Kong 3 and Donkey Kong Jr. Math don't share the same amount of stages, they appear to be similar enough to be beaten at the same time with the same controller input.
This movie improves on the previous movie (http://tasvideos.org/3361M.html) by playing an additional two games as well as improving by 3.99 seconds.
If you like this movie, you may want to check out movies (http://tasvideos.org/2636M.html) of (http://tasvideos.org/871M.html) other (http://tasvideos.org/1555M.html) games (http://tasvideos.org/1894M.html) in which as many as four games are played simultaneously with one controller.