Walkthrough

Air Defense Bunker

After things go...poorly for your squad during their descent to the surface of Stroggos, you'll be separated from most of your teammates, and be tasked with finding them by passing through a massive Air Defense Bunker. Get started by talking to the other soldiers near your position; the medic here will be able to heal you. If you pass by other medics in the future, just move your crosshairs over them and press your fire button to request a heal. Handy!

After that, start moving through the bunker, doing your best to stay alive. Fire on the Strogg guards from as far away as possible, since your blaster is more accurate than their weapons, and avoid any explosive barrels that you see, since enemy fire can detonate them and severely damage you. After you lose your first teammate, you'll pick up a machinegun, which will let you much more easily damage the Strogg that are coming after you.

You're restricted to a somewhat straight path here, so just head through whatever unlocked doors you can find, being careful to take down enemies from as far away as possible. Besides the lightly-armed Guard enemies, created from the bodies of fallen humans, you'll also encounter your first Brute, a massive Strogg warrior that chooses to enter into melee combat rather than fire at you from a distance. As you might surmise, these guys are big, hit hard, and take a lot of damage, so back away from them while unloading machinegun rounds into their bodies.

The Berserkers will be a constant threat to you throughout your journey.

When you reach Badger Squad, you'll be asked to return to the landing site and return with the Medic you passed by there, so double back and start heading back the way you came; you will of course run into more enemies on your way, including an Berserker, another humanoid Strogg with a spike on one hand and a hammer on the other. These guys are also melee attackers, and do severe damage when they hit you, so keep your distance!

When you've reached the medic and are on your way back to Badger, watch for a Brute that pops up out of the ground. When it's dead, drop down into the hole through which it came to find some armor, then flip the switch near the ladder and climb back up to continue on your path back to Badger.

Having satiated Badger's yearning for a medic, you'll finally be freed to leave the bunker, and you'll immediately meet up with Cortez, Rhino Squad's sharpshooter. From there it's a short, uneventful walk to the end of the level.

Air Defense Trenches

This is a fairly short level, so get moving. You'll initially be tasked with moving through the upper walkways of the Bunker, but you'll eventually reach an exterior area near the Trenches. Drop over the railing here to find some armor shards. When you reach Bidwell, you'll get a new objective: he wants you to enter and destroy the aircraft hangars nearby, since the fighters that they're launching are preventing your squad from advancing on and destroying the Air Defense Gun.

You'll have to fight through the Trenches with Morris until you reach the exit, so head on through to the Hangar Perimeter.

Hangar Perimeter

The first baddie you'll encounter here is a Gunner, a large humanoid Strogg that's armed with both a nailgun and a grenade launcher. When he fires his grenade at you, let it go past you, then run forward to avoid the blast.

Soon afterwards, you'll come to Corporal Mahler and his small squad. You'll get a shotgun at this point, but it won't be immediately useful to you, since the next fight takes place in an exterior area, and it won't be able to really hit anything at the distances you'll be working with. Note that there's both a Tech and a Medic in this squad, so whenever you have a chance to pause, get them to repair your health and armor by running up to them and hitting the fire button. Since you can always heal yourself up, be sure to stay out in front and take as much of the enemy fire as you can.

Watch out for the ambush in this room!

After the short elevator ride, you'll come up to an engine factory. There'll be a Gunner atop the walkway here, so watch for its grenade while you take it down with your machinegun. After that's dead, kill off the rest of the Strogg here, and you'll eventually be told by Mahler to find some way to bypass the reinforced glass nearby. While he's talking, watch out for the Berserker that'll pop up out of the nearby door; if you don't get in front of him, he might kill your medic.

Go through the nearby hangar hear, climb up the ladder, then walk back and flip the switch to extend the walkway above the hangar. Only one part of this switch is actually selectable, so be sure to click the correct spot on it. When the walkway is down, walk over it to reach the engine room again. Drop an engine down and fire it off to blast through the glass.

When you reach the next walkway that has to extend, you'll be accosted by numerous guards on the far platform; use your blaster on them to save your ammo until an Berserker comes your way. There's a ladder on the far end of the platform, so drop down there to find some more ammo and armor, should you need it. From there it's a short walk to the Interior Hangar.