You'll start off the chapter by being reunited with Rico and his Raiders. The first part of the battle is an on rails flight against the Helghast forces. The rest of the Raiders will be good at taking out the fodder, so concentrate your own attacks against the main targets: enemy turrets and anti-air troops.
After circling around the building a few times, you and Rico will get shot down. You'll land on a frozen beached tanker and will need to cautiously patrol ahead. Rico will provide good suppressant fire, but you'll have to be the one to take down the bulk of the foes. One of the new enemies are Helghast with jetpacks. Their high flight antics can make targeting them annoying, but thankfully they aren't any more durable than the rest of their allies.
Mount up with one of the stolen jetpacks and head to the rig. You'll want to make use of the jetpack's thrusters to leap across the broken bits of the rig. The jetpack has unlimited machinegun ammo along with missiles that have a cool down. Move to the far right of the building and take down the huddled group of soldiers. Next move inside the small shack and cleanse the remaining Helghast from their world.
Move to the rig's long plank and dive down to the ice pads below. You'll once again need to thrust up and forward to platform across the snowy land masses. Gun down the Helghast patrols ahead and enter into the second ice rig.
You'll be moving and jumping across broken catwalks. At every turn there will be more enemies to block your advance. Take the time to lovingly murder each one of them with special care. You'll need to strap in two bombs via the Sixaxis or Move. If you have trouble finding where to plant the bomb, use the objective marker button to point you to the correct hubs.
After arming the bombs, you'll have four minutes to escape the rig. Take out the jetpack Helghast that emerges from the gates and fly up the broken stairwell. You'll need to be swift about turning, as the enemy will appear behind you as you ascend the shaft. After reaching the top, quickly bolt to the objective marker to make it off the rig.
After another scene you'll be back on Rico's turf. Quickly sprint forward to avoid being blown up by the enemy cannons. You'll come to a stairwell along with a rifle. Rico will act as a meat shield while you peck at the enemy troop's meaty heads.
Move to the roofs and man the mounted cannon. Like all mounted weapons, this canon has infinite ammo while locked down. Use the missile barrage to take down the ships that appear. Several waves appear, so you may want to take cover while the cannon cools off. After taking down the heavy ships, dismount the heavy weapon and head back below.
Rush across the snow to the other end of the field. Even with the heavy gun in your hands you can switch out to smaller weapons. Conserve your rocket ammo and take down the Helghast guards with your sidearm. Head to the top of the building and blow up the tank in the distance. Use the remaining heavy ammo to kill off remaining guards and continue on to the next section.
After meeting with Jammer you'll be able to stock up on extra weapons. Grab a sniper rifle and a rocket launcher. Try to avoid using all of your ammo on small groups. Instead fire out of iron sights to use only one missile at a time. Slowly climb up the mountain face, sniping each guard that comes through.
At the top, there will be a shack on the right that contains an ammo dispenser. There is a lone Helghast inside, so be quick about killing him with your sidearm. Quickly grab an assault rifle and take cover. Pop out from cover and kill the guards in the opposite buildings. With luck, Rico will take the left side and provide good cover fire. After the fight head into the building to find the tram, which is one its way to Narville's prison.