Sideflip
A sideflip is a type of jump that can be executed while Mario is moving and provides him with a decent amount of height. It is performed by quickly reversing direction and then pressing the jump button.
Properties
Sideflips have a height of 496 units[1], giving them an identical height to both backflips and vaults. This height is fixed, meaning it is not determined by how long the jump button is held. In addition to gaining height, sideflips also move Mario laterally by a small amount in the direction that the stick was reversed to just before the jump.
Due to this lateral movement, sideflips are useful in very similar situations to backflips, which follow a similar path. One such example would be to clear an overhanging ceiling. The key difference is that sideflips are sometimes slightly better for situations where Mario is already moving prior to the jump.
Speedflip
In the direction perpendicular to a sideflip, Mario's speed is not capped, meaning one can, under the right conditions, build up infinite speed in this direction.[2] This is known as a speedflip. Mario's acceleration in this direction is proportional to the component of the left joystick pointing in that direction, with a maximum acceleration of 0.075 units/frame2.
Speedflips currently have little use, but some proposed applications include finding a new infinite fall, and, combined with nut sliding, a new way to collect the Third Courtyard Outskirts moon in Bowser's Kingdom without capturing anything.[3] A speedflip has also been used to jump from the painting island in Bowser's Kingdom to the Third Courtyard Rear island.[4]
Mario's speed in the direction of the sideflip and his speed perpendicular to the sideflip are completely independent. This makes it possible to vector a speedflip, squeezing out just slightly more speed (though the acceleration is unaffected).