In Metroid, the room's appearance very simply consists of blue circular tiles in the ceiling and walls. Thirteen platforms exist above the acid, which Samus can use to safely cross the room. Complicating this are Geegas that repeatedly spawn from nine points in the acid. Zeelas and Sidehoppers are also present here, making the trek difficult unless Samus has the Screw Attack and/or the Ice Beam.
In Zero Mission, the room's appearance and role have changed significantly. It is much longer in length and cannot be fully explored until after Unknown Item 2 (the Space Jump) has been obtained and the ancient Chozo machine has been reactivated. The corridor consists of two parts: a dry platform with a narrow passage through which the Morph Ball can fit, and a long basin filled with acid. A Chozo Block obstructs the narrow passage, which cannot be removed until Samus has the item. After defeating Kraid, Samus can return to the main shaft through this room. She can use a zip line on the ceiling, or alternatively Shinespark through the room if she quickly runs in from the corridor below with her Speed Booster charged. Should Samus fall into the acid, she will fall into the room below through a secret flowing waterfall of the substance. All enemies in the room have been replaced by a swarm of Reos, which follow Samus if she does not engage them, until she reaches the narrow passage.
- "Kraid entrance shaft" (via Red Hatch in Metroid, Blue Door in Zero Mission)
- "Block column shaft" (via Blue Door)
- "Acid fall" (Zero Mission, via drop in acid)
- 10 Reos
- 102 LOOK OUT BEHIND YOU (pg. 50)
- "The path back to the main shaft is flooded with acid. The only safe passage is a track along the ceiling. While you use a carrying mechanism to slide left, a swarm of big bugs will pop out of the acid and follow you. Face right and fire missiles into the crowd. When you arrive at the left side, fire at a Chozo Block to gain access to a narrow passage."