As in the previous level, the map is entirely indoors, and the player will have to swim underwater from time to time and activate certain devices in order to open hatches or change water levels.
Quick Level Completion
Differences from Easy to Normal
Differences from Normal to Hard / Hard+
#1: When inside the tumbler, aim up and shoot a switch hidden above it to access a chamber with Adrenaline in it.
#2: Just past, when you reach dry land again, turn around and shoot the Strogg symbol behind you to gain a Super Shotgun.
#3: In the cramped, pipe-filled room, there is a ledge full of Armor Shards. Jump across, and head to the right behind the pipes to find a little nook with a suit of Combat Armor inside.
#4: To get the DualFire Damage on the ledge, go to the room above and leap onto the windowsill. You can crouch-walk through this gap, which will let you walk out onto the side girders, giving you a clear jump to the power-up.