Block Shifting Glitch

The Block Shifting Glitch is a glitch in Metroid 2 that allows you to move blocks. However you can't decide which blocks to move and where you move them. It is done by rapidly pressing the Select button over and over again while moving vertically (you can't move in any other direction) while causing the screen to scroll. It is very useful to reach Secret Worlds and for Sequence breaking. It is officially illegal to use in Speed Runs.