What makes this even better is that, if you avoid shooting her, you will see Mother Brain move around and shoot at you much more frequently. It doesn't make the fight any harder, it's another, especially satisfying piece of attention to detail — Mother Brain knows full well what Samus has taken from her, and, after having killed the baby Metroid, is rightfully terrified.
Even with the Bittersweet Ending, there is one cathartic detail that remains. Samus killed the entire Space Pirate army in just a single day. She went to Zebes and plowed through every general, every Mook she could find. Phantoon, Draygon and Crocomire? Simple mere fodder to her. Kraid? He did survive Samus before, but she proved that lightning could not strike twice. Though he does make an unexpected return in Metroid Dread, he's a prisoner of Raven Beak and horrifically tortured for no apparent reason other than Raven Beak's amusement. Ridley? The space dragon who is notorious for cheating death multiple times, the one who has hunted Samus more than any other pirate is finally, truthfully dead. Mother Brain? She came damn near close to getting rid of Samus herself, but one Heroic Second Wind and Villainous Breakdown later, it was her demise that finally put an end to the pirates. After Zebes suffered an Earth-Shattering Kaboom, even despite the planet being Samus' home and the last Metroid dying off, Samus could still celebrate a victory that was greater than any other she's ever had in the series, as temporaryas it was: All of the mainstay antagonists are dead.
