Metroid X is the first Metroid-series hack to be released, and it's astonishingly compotent for what it is. It was created with the express design goal of providing a generally less frustrating and disorienting take on Metroid 1. By and large it manages to achieve that goal, though it might have possibly gone a bit too far (the map is all branches except for two loops). It would take over a decade for another M1 hack to be released that showed a comparable level of competence in design.
Like most hacks released prior to Editroid in 2010, this retains the basic skeleton of the original game's map due to the difficulty of properly moving items back then.
btw, I have a website I'm putting these things on now: