Sector 2 (Cryosphere)
The Cryosphere, also known as Sector 2, is a simulated-environment sector on the Bottle Ship and is the last such sector Samus Aran explores. It is a frigid area; scattered throughout are massive icicle stalactites and various icy platforms, all coated with the incessant snowfall. It also possesses a number of lakes, a few of them frozen. As with the Biosphere, the Cryosphere's environment extends into the sector's mechanical structures. Many corridors have a combination of snow and ice, and a few even have large chunks of ice blocking doors, inhibiting progress until destroyed. It is unique in that it has long, steep slopes, and certain portions of the sector (those leading to Sector Zero) have bizarre gravity fields, one of which is stronger than average, while the other is reversed (those who enter it end up walking on the ceiling rather than on the floor). It is unknown if the Cryosphere's climate as encountered is its intended climate, for Samus is alerted of an irregularity in the sector's climate control mechanism while traveling there from the Main Sector.
Because of the Cryosphere's temperature, lifeforms are scarce in number here compared to their numbers in other sectors, but it is far from tranquil. Notable inhabitants include Super Zebesians armed with Wave Beam technology, Kyratians, a Groganch (first seen in Sector 1), and the massive, armored, and intimidating Gigafraug. The Rhedogian is first encountered here, and a monstrosity known as Nightmare is also present, guardian of the entrance to Sector Zero. It is capable of manipulating gravity fields, presumably including those in the rooms leading up to it. However, as these fields are present following the creature's defeat, it is not known what causes them.
Notable events in this sector include the murder of Galactic Federation 07th Platoon member Maurice Favreau at the hands of a Galactic Federation-garbed assassin and the first sighting of a mysterious woman, presumed to be a survivor of the incident that prompted the transmission of the "Baby's Cry" distress signal that brought Samus and the platoon to the Bottle Ship. It is also the only sector in which Samus is attacked by the aforementioned assassin, who pilots the RB176 Ferrocrusher and tries to kill her with its plethora of lethal features. As such, the Cryosphere is where Samus is introduced to the idea of a secret assassin having infiltrated the platoon and where she dedicates herself to discovering the assassin's identity. Samus also discovers signs of Metroid predation here, even though Metroids cannot survive cold temperatures and are extinct.
- "A Level 4 warning is now in effect in Sector 2. An irregularity in the climate-control systems of Sector 2 has been confirmed. Please be sure to wear protective equipment and use extreme care when moving around this floor." —Bottle Ship PA System (Metroid: Other M)
- "How can I trust you when your troops are willing to kill each other?" —MB (Metroid: Other M)
- "Was she the one who sent the distress signal? And could she be the person in charge here: Madeline Bergman? Either way, I knew I had to protect her. She would be targeted again." —Samus Aran (Metroid: Other M)
- "At this rate, the plan the Federation wanted to keep so secret would be revealed. So they sent in an assassin. Someone to wipe out any survivors as well as anyone who learned about the secret project." —Samus Aran (Metroid: Other M)
- "The creature's corpse showed signs of what looked like Metroid predation, making my mind race. Metroids... here? Impossible. Metroids can't tolerate cold temperatures—they couldn't survive in this environment. Besides, they're extinct. The baby was the last of its kind..." —Samus Aran (Metroid: Other M)