This is a tool-assisted speedrun, made on an emulator, using frame-by-frame shooting, savestates, and rerecords to overcome reaction time and human error. As such, it is purely a form of entertainment, and is not designed to show skill.
Ever wonder if Mario was actually a ninja wearing blue overalls? Now you know.
This run completes the game after collecting a mere 16 stars. It was originally intended that the player collect a minimum of 70 to finish, but a few bugs allow Mario to pass through doors and barriers that require a minimum number of stars to open. This is also used when unlocking a door would take longer than setting up and executing the bug.
Mario has a very wide range of skills for mobility and some of the physics of this game are easily abused by an experienced player.