This serves as the entrance to the main area of Brinstar, and in particular the green jungle region. It is not the first room Samus visits in Brinstar as a whole, given that she revisits the first three rooms of "old Brinstar" before coming here. During her mission, this room serves as a main hub for her exploration of Brinstar. It connects directly to a Save Room, the room where the Early Super Missiles technique can be performed, and the Dachora's room. It also connects indirectly to Brinstar's Map Computer and the area's only Missile Charge.
In terms of appearance, this room is a long vertical shaft of mostly organic material. The walls appear to be formed out of thick, green thorns, with multiple midair and wall-mounted ledges made of a green moss-looking material. At the very bottom of the shaft is a floor composed of Power Bomb Blocks; when destroyed later in the game, a secret undershaft is exposed. This has more platforms and a Locked Door that cannot be entered from this side. Samus can continue from here into a shaft populated by the Etecoons, who teach her to Wall Jump. If she Wall Jumps up to the top of the shaft, she can re-enter the undershaft of the Main Shaft through the locked door, which is open on the Etecoons' side. If Samus is unable to Wall Jump to the door, a hidden tunnel in the Etecoon shaft provides an alternate escape route, allowing her to leave the area.
- "Transport to Brinstar" (via Elevator)
- "Map Station Access" (via Red Hatch)
- "Early Supers Room" (via Red Hatch)
- Brinstar Save Station 1 (via Red Hatch)
- "Green Brinstar Fireflea Room" (via Red Hatch)
- "Dachora's room" (via Red Hatch)
- "Beetom trap" (via Blue Door)
- Hell (via one-way tunnel and Locked Door, which can only be opened from the other side)
- Page 47
- "Set off a Power Bomb to blast the sturdy floor away."
- USE THE POWER BOMB (pg. 29)
- "Use the power bombs to blast your wy[sic] throught[sic] the floor."
- One of the clips in the Super Metroid attract mode shows Samus using the Plasma Beam Special Charge Beam Attack on a group of three Zeelas in this shaft.