"Enter Lethia Imulsion Facility"
Scout the Factory Entrance
You and the squad are abandoned outside of the Imulsion Facility when the Junker broke down on you. You need to find a way in, there may be parts inside that they can use to repair the vehicle.
As you approach the factory entrance you learn of a new Wretch breed, the Dark Wretch. They are more dangerous than the normal Wretch because they explode when killed, they also have a eerie green glow because of their exposure to the imulsion.
You and the squad then split up as you discover the main door is locked tight, and Anya has no other known entrances. You and Dom take one path, while Baird and Cole take the other.
Find an Entrance to the Factory
You and Dom work your way around the factory, searching for another entrance to get inside. You also face your first batch of Dark Wretches, take them out from a distance because if they get close you are sure to kill yourself when they explode.
Eventually you'll reach an area with a non-working elevator. To activate it you must goto the next room over to turn it on. On heading back to the elevator, be careful of a few Dark Wretches that pop out near the elevator.
Once the elevator takes you to the roof of the shack, you can gain access to the factory using a window.
"Keep your distance from Dark Wretches"
Find an Alternate Route
You call the rest of the squad, to find they found a way in to the basement of the facility. Anya informs you to find the Cart Control Room to use the carts to gain access to the mine.
To move out of this room, you need to activate the switch at the end of each hallway.
Find the Cart Control Room
As you progress, Baird finds a way to turn on the lights. Just your luck as you get to see a room filled with Stranded corpses strung about after being a meal for the Dark Wretches.
Inside the next room you come across an ecstatic Stranded who thinks you are his rescue team. Lucky he knows the facility well and can guide you down to the cart control room.
Continue to follow him, but watch for a Dark Wretch or two that may pop out of the walls or vents to attack. Eventually you'll reach a room with a wooden plank floor that isn't very sturdy. The Stranded will fall through and be eaten by the Dark Wretches below.
Just past that room you will reach the mine cart room, that fills up with about ten nasty Dark Wretch. Take them out quick and avoid going into cover.
A room ahead on the right will contain a valve that you can turn to open the doors. Once behind those doors you will meet back up with the rest of your squad. You may want to have them take a shower first though. Open the gate with the valve on the wall.
In this next area, all seems well until the squad spots a Dark Wretch on the ceiling. After that all hell breaks loose. You have some Dark Wretches along with Drones and Grenadiers to clear out. You have the whole squad back together, this shouldn't be too hard.
Once they are cleared out, you find a door to break through at the end to get to the control room. It's stuck shut, so Jack needs to open it. Too bad a Boomer has just decided to drop in on you. Take cover and take out the Boomer and the Grenadiers he brought with him. Toss a few Frag Grenades ever so carefully at their feet as the elevator touches down. You can find them on a stair ledge in the opposite side of the room.
Once in the cart control room, you need to find a switch to open the path to ride the carts on. The switch can be found in the room on the right. Also load up on Ammo here, there is plenty laying about in the control room.
"Mechanized death ride"
Ride the Carts to the Core Room
Find a cart and hop in for the ride!
There are two paths through this area, which depends on what cart you get into while at the station. The paths cross a few times, but the one you take will determine how close you are to various enemies along the way.
You are now in your mine cart, heading through the Imulsion Mines. Stay crouched in your cart and blind fire your Lancer at any enemies you may see.
Get To the Core Room
Marcus and Baird are split off from the rest of the squad for this short trip to the core room. Fight through a few Dark Wretch in the machine rooms to reach the drilling platforms.
Ride the Platforms Down to the Caves
Once Anya raises the drilling platforms, take down the Boomers that decides to come along for the ride as well. Toss a few grenades their way to make shorter work of them.
Now hop on the platforms to get down into the caves.
Darkest Before Dawn
"Traverse the caves before the Kryll come home"
Locate the Pumping Station Before Dawn
Traverse the Kryll caves here to find the pumping station before the Kryll return home at dawn.
You'll come across about half a dozen Dark Wretches that prompts Marcus to have Baird to stay back and protect Cole and the resonator. Be sure to grab the Longshot on the lower platform before continuing on.
Regroup with Baird and Gus
As you and Dom continue forward, you fall down a slippery slope. So Baird and Gus will have to find an alternate route to meet up with the squad later.
Further up the path you'll come across some Drones, Grenadiers and a Sniper. Take them out with your Longshot or Lancer. Bust open the door here to get some extra ammo and some Frag Grenades.
As you proceed down the path you will get shot at from a Locust Sniper. He is hard to see up in the cavern, but you have two methods of dealing with him. You can use your Longshot and fire back at him from cover, or you can shoot down the Weakened Column of stone that he is right next to with your Lancer. I'd go for the stone myself to conserve ammo and for a bit of enjoyment.
In the next few areas, you'll just run into some Dark Wretch. Nothing too hard here, also be sure to keep an eye out for ammo drops along the side passageways. You'll need some for what's up next.
After the second group of Dark Wretches there is a Boomer to deal with. Take cover and take him out with your Longshot. A few good headshots should do it. Let Dom take care of the few Dark Wretch that come after you as well here.
Just past the Boomer you and Dom fall down again, this time through a covered hole in the ground. As you land you are surrounded by Dark Wretches. Luckily thanks for their explosive tenancies they leave a new path for you to continue on through.
A bit further and the squad decides to split up again to cover more room because time is running short.
You travel amongst the high road, just to the left of Dom. You will face one Drone and a few Dark Wretches. Take them out and help out Dom on the left by taking out the Drone who is undercover out in the distance.
Eventually the paths cross and now you are on the Left Side of Dom. You have a few more Dark Wretches to clear out along with a Grenadier on each side of the path. Help Dom out when you can.
Once you are cleared you will be reunited with Dom.
The Left Path is almost identical to the right path. Just keep an eye out on Dom to make sure he is not in harms way.
Back with Dom
Once you reunite with Dom, drop down into the lower area on the right to load up with some more ammo.
Further down the path, you will find a cavern off to the left. Follow that through and clear out the Dark Wretches and the Drones that come your way.
After there you will get a teaser from the Corpser again. But this time it feels like there is a battle coming up. Grab any ammo you can find, you will need it!
"David versus Goliath"
Kill The Corpser
Time to do battle with the Corpser.
As the battle starts, run to the left side of the Corpser to fill up your ammo. Back away from him and wait until he lifts his front legs to attack you. When this happens, avoid his strikes while shooting him in the brown abdomen. When you shoot him here, he will open his mouth. At this point, you must shoot him in the mouth to make him back up. Repeat these steps until he backs up onto the platform. As he backs up, you will be attacked from behind by Dark Wretches. Remember to avoid these when you kill them because they explode.
When you've backed the Corpser up all the way, you'll notice that there are 2 metal plates connecting this platform to the rock you're standing on. Go to each of these and wait for the corpser to try to strike you. Dodge his legs and he will smash the plates. Then just sit back and watch him fall into the immulsion and die. Alternately if you have a shotgun, you can go easy mode and shoot out the plates yourself.
Reunited after drowning the Corpser in imulsion, the squad continues their search for the pumping station.
Tip of the Iceberg
"More mysteries found"
Secure the Pumping Station
As you find the pumping station, you will be walking along a giant pool of Imulsion on a rock island. On the right just a bit from the start is the first appearance of the Torque Bow, pick it up I'm sure there is a use for it ahead.
As you approach the station itself, the squad breaks into two groups to handle the enemies ahead. This is important knowing what awaits the squad ahead.
As you approach the station, you are confronted by a new type of Locust, the Theron Guards. In the words of Marcus "Ah, shit. Looks like they upgraded!". The Theron Guard are not only smarter than the Drone of old, but they carry better weapons like the Torque Bow and the Gnasher.
You'll face about two waves of three to four Theron Guards each. Take some out with the Torque Bow from afar, and then move in with Dom to clear the rest out.
Restore Power to the Elevator
Now that the area is clear, you reunite with the rest of the squad and deploy the resonator. Bye Bye Locust!