This is a tool-assisted speedrun. For more information, see
Mario & Luigi for MS-DOS is an independent game created by aspiring coder Mike Wiering in 1994. Although it’s limited in some ways, the game is reasonably solid and shows decent smooth-scrolling graphics for a 25MHz 486.
Here, veteran DOS TASer Ilari () uses tricks requiring exacting precision to squeeze every last millisecond out of this 6 level game.