: In the final confrontation with the bio-mechanical Mother Brain , Samus is nearly defeated. The Metroid hatchling—now grown to a massive size—recognizes Samus as its "mother" and sacrifices itself to give her the Hyper Beam , allowing her to destroy Mother Brain and escape before the planet self-destructs. Why the (JU) Version Matters
: To reach the final area, Tourian , Samus must defeat four primary guardians: Kraid, Phantoon, Draygon, and Ridley.
The story follows bounty hunter as she returns to the planet Zebes to rescue a stolen Metroid hatchling. The Narrative Arc
: Shortly after Samus departs, the colony is attacked by the Space Pirate leader, Ridley . He slaughters the scientists and steals the hatchling, prompting Samus to follow him back to the Space Pirate stronghold on planet Zebes .
The "JU" in stands for Japan/USA, referring to the specific ROM version that contains both English and Japanese text. This version is widely considered the standard for fans, speedrunners, and ROM hackers.
: Following her previous mission on SR388, Samus delivers the last surviving Metroid to the Ceres Space Colony for scientific study. Scientists discover its energy could potentially benefit humanity.
: Samus explores the subterranean world, navigating diverse biomes like the rainy surface of Crateria , the overgrown Brinstar , the volcanic Norfair , and the sunken Maridia .