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The "acid fall" is a room in Kraid's Lair/Kraid. It appears, with significant differences between versions, in Metroid and Metroid: Zero Mission.


In Metroid, this is a simple corridor that reuses certain assets found elsewhere in Kraid. The rightmost part of the room consists of blue brick-like tiles with the entrance door on a ledge, and a blocky overhang from the ceiling in front. A single Air Hole and small fissure filled with acid is found here. To its left is a wider pool of acid with pillars forming a "staircase" of sorts. A Missile Tank can be found on the middle pillar. This is the primary reason for coming to this room. The wall on the left is made of white bricks and black rocks, and is part of the ceiling for a different room.

In Zero Mission, the room's appearance has changed drastically. It is now longer and made of purple architecture, with a single pool of acid. A waterfall of acid also flows into here from the corridor above. It is possible for Samus to fall into this room via the waterfall (much like Maridia's quicksand falls in Super Metroid), which also slows her movement, and if she does not have the Varia Suit, damages her. The fall flows into the acid pool and is surrouned by a total of seven midair pillars, three of which have Zeelas crawling on them. The pillars lead to a sloped ledge on the left, with a Missile Tank embedded in the corner of the wall.

On the right side of the room is more dry land, a large platform with an Air Hole that spawns Geegas two at a time, and a larger slope. The slope is ideal for running until the Speed Booster activates. Samus can then quickly exit into the adjacent shaft, jumping up to the "corrosive pool's" door and Shinesparking in to get through that room faster.

Connecting rooms[]



Zero Mission[]

  • Geegas spawned 2 at a time from an Air Hole
  • 3 Zeelas


The Missile Tank in Zero Mission.

Missile Tank
In plain sight in Metroid. In Zero Mission, hidden in the left wall.

Official data[]

Metroid: Zero Mission: The Official Nintendo Player's Guide[]

101 missile tank (pg. 50)
"There's no avoiding the acid in the corridor that runs into the center of the lair. You'll jump through a flow on your way to the left side. Hit enemies from a distance to avoid damage, and find a tank in the left wall."