Crouch Lock
From A complete guide to Super Metroid speedrunning
A crouch lock occurs when Samus unmorphs while facing a direction and then the player presses the opposite direction on the directional pad while unmorphing. Although the player expects Samus to start moving that opposite direction when the unmorph is complete, she will not.
You can avoid this by turning around before unmorphing, or waiting until the unmorph animation is complete before turning around. As you practice a route, you should figure out which areas, if any, this would be a common occurrence in.
