Alright here the walkthrough for the next chapter. Chapter twelve : Surface Tension. This one is quite long chapter, so enjoy.
Once the door opens, you will finally be on the surface ready to help. Fight any soldiers nearby and travel down the road. You will see the dam in the distance. There will be many soldiers surrounding it. Travel onward to the dam. Neutralize the soldiers in any way you can. There are explosive barrels scattered around to make the job easier. Enter the parking lot to the dam and head straight forward over the water. A helicopter will appear and start shooting at you. Take cover from the chopper and fight it. It will soon fly away after taking damage. Move forward across the dam again while simultaneously fighting soldiers. Try to take the walkway to the right of the dam. The concrete walkway will collapse and send you plummeting into the water. Find the ladder at the back of the structure and climb up.
Throw the power switch and jump back into the water. There will be another ichthyosaur in the water. Kill it, then continue to the area where the water is bubbling. The current will sweep you into a new area. Swim away from the dam through the canyon. Get to the shore and find the pipes. Crouch through the left pipe and crawl through. You will come to a wall with a sign that says Lower Canal. move straight ahead.Take the ladder and drop down to the concrete ledge on the side of the cliff. When you reach the next ladder, climb up.
Be ready to fight multiple houndeyes. Head towards the building marked with a 2. Avoid the high voltage fence and take the road going through the mountain. Use the valve to open the gate. Fight the soldiers in the area ahead. Once they are dead, walk towards the building. To the left there will be a small control room. Use the button to open the access hatches. Kill the soldiers that will attack after. Travel towards the gate marked B and head in. Walk through the gorge to the minefield. At the entrance you can find a green box with unlimited grenades. Use the grenades to destroy the mines. Watch your step and make sure you destroy every mine in your path.
Move around the barbed wire and jump on the rocks. Use them to access the nearby ladder. Drop down and crawl through the pipe. Crouch through the pipes until you reach a cliff. Take a long leap to a rock below you on your left. Kill the soldiers on the cliff. Continue across the ledge while fighting soldiers. Eventually you will come to a broken catwalk. Kill the soldiers on the other side. Make a running jump to the piece of metal sticking out of the other side of the gap. Head into the control room for health. When you’re done, walk down the pipe to the structure. Descend from the structure while fighting soldiers. Use the catwalk at the bottom to reach the other side of the cliff.
Travel around the ledge until you come to a storage facility door. Press the button and wait for the door to open. Destroy the sentries in the room or avoid the red lasers.
Enter the small office and grab the missile launcher. The helicopter will return when you step outside. Use the rocks as cover while you battle the helicopter. The missiles are laser guided, so keep your crosshair on the helicopter. There are rocket supplies in the green box, so make sure you resupply. After enough hits with the missile launcher, the helicopter will go down.
Walk around the ledge until you reach a ladder. Climb up and continue your ascent up the cliff. You will reach more gaps in the catwalk.Jump across the catwalk debris until you reach the next ledge. There will be a pipe leading through the cliff. Crouch through all three pipes and climb up the next ladder.Walk into the gorge and into another set of pipes to your left. There are multiple directions you can go. In the middle, there is a large yard full of soldiers. Try to avoid them.
Go around the side and avoid gunfire. Swim around the area until soldiers throw explosive barrels at you. Dodge the explosions and head into the pipe at the end of the flooded area. Follow the tunnels until you reach a ladder leading to a road. When you emerge there will be a tank in front of you. Take cover in the building on the right. The tank will shoot a hole in the wall. Take cover and fight the soldiers. Beware of the tank, it will still try to shoot you.
Destroy the tank with your missile launcher and move forward. Find the small security checkpoint and press the secure access button. Move down the road and watch out for the next tank. Once the second tank is destroyed, continue forward. Kill any soldiers that get in your way. Enter the road tunnel and jump through the broken window to the office. Press the button on the wall to open the tunnel door. The off-road area will have landmines, so watch your step. Walk around the building towards the right and find the alley. Avoid the explosive blue lasers.
When you reach the end of the alley, snipers will target you. First they will pick off a scientist who was trying to assist a security guard. You can take out the sniper with a precisely placed grenade, or dodge his shots. Move across the road and watch out for land mines. Open the door to the building straight ahead. Continue until you find a door to the next area. Head towards the electric fence. Crouch under the high-voltage fence. Another sniper will target you. Take cover and run in-between shots. He can also be taken out with a grenade. Disable the electric fence by turning off the power on the wall of the building, near the downed tower.
Climb the downed tower to get to the roof. Jump through the broken ceiling to get inside of the building. Find the scientist and talk to him. Go through the door. You will need to avoid the blue lasers. Do not cause any explosions. Move down the hall and press the green button to open the door. Open the next door and enter the room filled with blue lasers. Once again, do not cause any explosions. Dodge the lasers one at a time and make your way through the room. Use the objects scattered around the room to get higher up so you can bypass difficult lasers. Now is a good time to remember you can crouch jump and sprint to get an extra boost.
Once you reach the other side of the room, activate the lift. There will be a wooden box that is on the path to hit a blue laser. Destroy the box before it causes an explosion. Use the lift to sprint-jump to the center of the room. There will be a corpse on the center lift, and you will acquire a new weapon. Ride the lift down to the next level. Fight the soldiers on the street. Take the walkway to the right of the road. Follow the road with the truck on it. The truck will have a sentry in the back of it. Destroy the sentry and move on.
Follow the road until you are attacked by both aliens and soldiers. Avoid the carpet bombs. A tank will drive out of the tunnel. Destroy the tank and the rest of the hostiles in the area. Follow the road to the right and find the alley. There will be a sniper in the window. Dodge his shots or kill him. The red door to the high security storage facility will be cracked open. Enter and kill the soldiers. Go inside and find the set of stairs. Continue forward until you find the Area 3 security checkpoint. Talk to the security guard and wait for him to open the door to the armory. Take everything you need and exit the armory through the door at the back of the room. Jump across the alley to the platform on the other side. If you fall, you can use the ladder to climb back up quickly. Enter the second red door.
The second floor of the building will be mostly destroyed. Jump down and kill the soldiers on the first floor. Use the destroyed pieces of floor to jump safely across the building. When you get to the other side, drop down and head to the street. Kill any aliens and soldiers in the area. There will be ammo and rockets available at the green supply cases. Destroy the helicopter and move into the fenced-in helicopter area. Move across the helicopter pad towards the road. Walk down the hilly road to the tunnel. Enter the door to the left of the tunnel and go up the stairs. Use the mounted tow launcher to destroy the tank on the helicopter pad. There will also be rocket ammo scattered around the room. Drop back down to the road and move to the helicopter pad. Enter the tunnel where the tank came from. Use the mounted machine gun to kill any enemies that will appear. Run to the end of the tunnel and take the door to the right.
Find the ladder leading into a vent. Follow the vent to the next road. The vent will fall and you’ll be left facing a big enemy. Turn around and sprint. Reach the end of the tunnel as fast as you can. Exit the tunnel and let the creature stop on his own. He will be distracted by a small tower. Use one of the alien-jumps on the ground to reach the top. Use the monitor to call in a missile strike on the creature. Use the overhead view on the monitor once again to call in a missile to the small radio tower. It will fall creating a bridge into the parking lot. Open the tunnel door using the red valve. The road will now be open. Travel forward to the end of the tunnel. Enter the door to your left. Find the security guard listening to the radio.
Thats it for this chapter 12 Surface Tension, if you find it hard to follow my instruction, here is the video.