Part 13

When facing marines in the hallway, retreat to the top of the ramp to allow them to kill themselves with grenades, or crouch halfway down the ramp and shoot them as they appear. Alternatively, jump on the lower floor to get a better view of the upper walkways.

After clearing the marines, you can use the barnacle bridge as a shortcut, skipping some combat and supplies.

If not using the shortcut, jump onto the conveyor belt past the barnacle tongues to reach a room with assault rifle clips, a first aid station, and an HEV wall station.

Locate the lowest green crate in the large crate stack, then jump from crate to crate to reach the highest green crate.

Jump from the highest green crate to the high-up conveyor belt and follow it to a room.

Quicksave before entering the room. Move in just enough for the marine on the other side to see you, then quickly back up near the conveyor bend.

Wait for the marine to move next to the explosive barrels, then shoot the barrels to kill him. If the marine blows up the barrels, damages you with a grenade, or replicates, quickrestore and try again.

As an alternative, blow up the barrels as you approach the room, throw a grenade toward the marine's sandbag wall before he sees you, then charge him.

Search the marine's side of the room for a first aid station and ammo.

Look down to the lower floor and note the turrets and laser alarms. Quicksave.

Drop down to land next to the fire door's button, then go through the fire door and jump over the laser tripmine (quickrestore if anything goes wrong).

Turn left past the tripmine and move forward. Look up to see a marine's legs on an upper walkway.

Shoot the marine's legs, then wait for him to move towards stairs leading down. He should be caught and eaten by a barnacle.

Trick two other marines into the same fate. If a marine makes it past the barnacle, you will have to shoot him.

Quickly run up the stairs while the last marine is distracted by the barnacle, or kill the barnacle with your pistol before going up.

Look for shotgun shells on a small green crate near a sandbag wall.

Go up more stairs and run along the walkway until you can turn left into a wide concrete corridor.

Continuing past this point on the walkway leads to a first aid station and assault rifle clips past a barnacle.

Go down the concrete corridor and across another barnacle-tongue bridge.

You will reach an upper walkway over an area where marines were previously killed.

Go around the walkway and bash crates to find an armor battery.

Locate the stairs leading down to a lower walkway, then take stairs to the floor where marines were.

Bash all crates on that floor for more supplies.

Find the large "SURFACE ACCESS" lift in the back and use its button to open it.

Get on the lift and use its interior button to ascend to section c1a3b.

If the lift jams upon loading, crouch and move to break free of the glitch.

After the lift stops, crouch-hop past it, turn left, and run for the corner with the first aid station. Stay left to avoid being seen by outside marines.

Quicksave. Go through the left side of the large doorway, immediately turn left, and run past two sets of wooden crates.

Turn right and run for the open door past another set of wooden crates. Crouch as you drop to the door on lower ground.

As soon as you are through the door, climb down the ladder to reach section c1a3c.

Finish climbing down the ladder. Bash crates for ammo and use first aid and HEV stations to recharge.

Move to the vent access door to open it. Back up as an explosion sends debris down the shaft.

Have your assault rifle ready in case of any remaining marines.

Quickly move through the vent access door and drop to the ledge on the right.

Turn and try to drop onto the broken fan before dropping to the metal walkway below.

Find the large opening in a wall next to the walkway and run down it to return to section c1a3.

At the end of the shaft, quicksave before dropping to the narrow ledge below.

Move along the ledge and enter a vent shaft.

Go forward until you see an opening on your right. Drop down onto a green crate.

Turn and crouch-walk under an unbreakable vent grating to get shotgun ammo.

Crouch-jump back onto the green crate.