Super Mario Bros. 2 is the American-released sequel to the famous Super Mario Bros.
Contrary to popular belief, it was developed from the ground up as a new Mario title with vertical scrolling, which the original game lacked. In the middle of its development, it was split off into Doki Doki Panic before being finished as Super Mario USA, a.k.a. Super Mario Bros. 2.
The game features warps and several unintended tricks and glitches which can add up to make a TAS even speedier.