Getting the Yellow Key (6)

Entrance: Open the compartment behind you for Scuba Gear and a Large Medikit. Go to the crack on the left wall for an RPG. Follow the pipe down, go down the waterfall, and fight the Octabrain. In a small nook, find Shotgun Shells. Continue to a rocky ledge, grab the Pistol and Large Medikit. You will be attacked by Enforcers and Sentry Drones; use the Chaingun Cannon if needed. Jump into the water.

Underwater: Sharks are present but not initially troublesome.

SECRET 1: Behind sea weeds on the wall is a crack. Blow it up to enter a shark farm. Defeat the sharks and collect Devastator Ammo, Chaingun Cannon Ammo, and Scuba Gear. Surface and prepare to fight Slimer Eggs and Octabrains on a ledge using RPG or Devastator rounds. Collect Devastator, Shrink Ray Ammo, Pistol Ammo, and a Large Medikit from the ledge.

Underwater (Continued): Collect Freezer Ammo on a rock. Near the rock, fight Octabrains and Slimer Eggs with the RPG. Collect Freezer Ammo and Body Armor. Between the building and the rock, fight Sharks and Octabrains. Enter a crack in the rock to find an RPG and Atomic Health. Swim up at the Atomic Health location.

Building Top: Use the Chaingun Cannon to fight Troopers and Captains. Find a Chaingun on a wall ledge. Ascend the ledges, collecting Chaingun Cannon Ammo, RPG Ammo, and a Large Medikit. At the very top, find the Blue Key and two Devastator Ammo.

SECRET 2: Jump into the back wall for a vantage point across from you on another building top, allowing you to take out Enforcers.

Blue Key Door: Underwater, near the building, find the Blue Key door behind foliage. Upon opening, prepare for many Octabrains; use the RPG or Pipebombs. Inside the room, find a Freezer and Portable Medikit near the entrance. Collect Devastator Ammo and Shotgun Shells on the ground. Further in, find the Yellow Key.