The catwalk is a large room with an extensive, three-floor catwalk. Each floor is divided by four sets of stairs illuminated with cyan and pale orange lights. The catwalk paths themselves are lined with smaller red, green and blue lights. The catwalk is entered from a a Navigation Booth connected to Experiment Floor 3, and it leads directly into the Biosphere Test Area. The door to that room locks permanently after Samus explores the Exam Center, meaning she cannot revisit it.
On either side of the room are four large tanks with tree-like specimens in them. The specimens have long, dark trunks and bright green leaves, and are surrounded by large pillar-like lights or radiators that change color from green to blue. Their purpose is unknown, but it is possible that the "radiators" are meant to induce photosynthesis. It is not possible to interact with the specimens and they are not affected by Wave Beam shots, which can pass through the glass.
At the top of the catwalk on the right is a Desbrachian gate, which cannot be opened until after the credits. Summoning it with a Power Bomb (only authorized near the end of the game) will allow Samus to destroy it and then claim an E-Recovery Tank. The door to the Biospere Test Area is on the upper left side. There is a higher ledge in the room near the bottom left, which contains a Missile Tank. It is not reachable from within the room however; to get to it, Samus must return to Experiment Floor 3 and run through a section of wall with her Speed Booster (after it has been authorized), which leads her to an alternate door taking her to the ledge.
- Experiment Floor 3 (via automatic door)
- Navigation Booth (via automatic door)
- Biosphere Test Area (via automatic door)
- Missile Tank
- Requires Speed Booster. By running along the track in Experiment Floor 3,
- E-Recovery Tank
- Requires Power Bombs. Found in the small room behind the Desbrachian gate. This is the only E-Recovery Tank guarded by a Desbrachian, and the only one found outside the Cryosphere.
- Page 71
- "The next room has two series of stairs leading to the Biosphere Test Area."
- "There is also a circular hatch that you cannot access just yet. You'll need the Power Bomb to open it up."
- Page 152
- "To get to this Missile Tank, return to the large room [Experiment Floor 3] leading to this one. Go all the way to the left edge of the room, where the paved road is, and back up. Get a running start toward the upper end of the room and use Speed Booster to bust through a dirt tunnel. This tunnel leads into the next room where the Missile Tank is."
- Page 175
- "Use a Power Bomb to wake the Desbrachian in this room and defeat it. Behind it is a hatch to a small room holding an E-Recovery Tank."