Zero Mission may not be commonly lauded as the greatest entry in the Metroid series, but what it does is refine the formula into what I believe to be the greatest display of the pure essence of the franchise. It modernizes the first game, adding so much in what should be considered the template of a perfect remake. New enemies, QOL improvements, additional lore, new and returning upgrades, flawless controls, and the freedom to go about how you want to play thanks to the variety of sequence breaks, which reward the application of game knowledge. I've sunk so much time into this game that there's a section of my brain practically dedicated to it, and I can't say that for a lot of things in my life.