This is a tool-assisted speedrun. For more information, see http://tasvideos.org/3648M.html. TAS originally published on 2018-03-07.
Once again, Bowser has kidnapped Peach, but this time Mario isn't trying to rescue her quite as urgently. Fed up with getting no reward for his endeavors beyond cake, Mario takes a leaf out of Wario's book and decides that while rescuing Peach, he might as well make as much money as he can.
In this movie, the aim is to complete the game while collecting every possible item without dying, doing so as fast as possible.