Location from Pikmin 2 by Nintendo / Shigeru Miyamoto
The second cave of the Valley of Repose — nine sublevels that begin in snow and end in rusted industrial darkness, with a machine-gun spider waiting at the bottom.
The Subterranean Complex is the difficulty spike. It starts easy and doesn't stay that way. The Armored Cannon Beetle Larvae, the Gatling Groinks, the Careening Dirigubugs — they have ranged attacks, and the bottomless pits mean one badly managed panic costs Pikmin you can't afford to lose. The Man-at-Legs waits on sublevel 9. The Stellar Orb it guards becomes the Solar System upgrade, which lights up caves going forward. Practical and welcome. The cave also contains some of the best farming locations for Purple and White Pikmin via Candypop Buds on the middle floors.
The upper floors look like the Emergence Cave: snow-covered, cold, pale. By the middle floors, the walls shift to metal and rust — bottomless pits appear, and enemies with explosive or projectile attacks become the standard. The lower floors feel industrial, like something's been left running that was never turned off.
Also known as: Subterranean Complex