Half-Life 2 Walkthrough -> Intruder #1
A battle between a squad of soldiers and zombies is raging below. Watch carefully (fast zombies can jump on us) and finish off the victor, then jump down and head to the opening through which the lambda sign is visible. To the left, behind the bars, are boxes with goodies. You can pull the boxes with the gravity gun, as well as the goodies. Then return and continue up.
Below, the turrets are desperately firing at the zombies. Throw them all a grenade, or better yet, two. Near the monitor is a health and armor replenishment machine. Wait near the monitor for the explosion that will blow out the door. If you stand near the door, the entire remaining squad may die.
Destroy generator
A behind the door. Alyx:
From here on, we'll work together again. After going through several rooms, recharging our armor and health, we'll descend to a locked room. We'll storm the locked room together—Alyx through the right door, everyone else through the left.
After the battle, Alyx will tell us we need to destroy the Combine generator in the square, but breaching the defenses will require time, during which time soldiers will attack us. After that, Alyx will open the third door in this room, and we'll exit into the square.
To the right and left are force fields, behind which soldiers will occasionally disembark. Use the pulse rifle, firing short, accurate bursts at the soldiers. Fortunately, the soldiers also use rifles, and ammo for them can be looted after they are killed.
Don't forget that ammo behind the force field can be attracted by the gravity gun. After Alyx hacks the defenses and all the generator shutters open, fire at it with the gravity gun. An energy ball should pop out.
Losing Your Girlfriend: After
breaking the generator, immediately go through the gate behind the generator. At this point, several Alliance elite will run up, but fighting them is completely unnecessary. Although you can shoot one, two, or three. A bridge no longer exists between us and the TNT sign.
Alyx climbs to the roof in hopes of finding another way out, and finds one, but she is captured by Alliance soldiers. Well, we'll have to proceed without her:
We jump down and go left, into the sewers. The first door is open. The second door is locked, but the bolt can be removed with the gravity gun. We knock out four beams and emerge into a long corridor, where there are manhacks.
To the right is a shield with boxes, which you can use to climb onto the pipes by knocking out the barrels underneath. We climb into the vents, left or right—it doesn't matter. Immediately below, to the left, are several manhacks. If necessary, go there for a first aid kit and armor, then return and exit to the right.
Three soldiers will run out from the top left, along with a crate of ammo that can be pulled in with the Gravity Gun. The exit from this room is two levels down, but even lower down is a Lambda sign and ammo, accessible via a ladder on a pipe. Jumping down is difficult, so use the Gravity Gun again. The exit is a gate bolted on the back. You can unlock it from the room with the poisonous headcrab on the right by knocking down the bolt with the Gravity Gun.
You can kill the soldier immediately, or you can back away and wait for him to kill all the zombies and headcrabs he can. After that, two more soldiers will appear below, but you don't have to kill them right away. At the end, behind a support, there's a first aid kit and armor, but don't knock it out! Pull everything in with the Gravity Gun. Then return and jump down to where the battle between the zombies and soldiers took place.
Around the corner, there's a staircase on the right. But this isn't a secret; it's the main route. First, we go straight ahead. Before the poison zombie on the right, there's a Lambda sign on the wall, and beneath it is a narrow passage with ammo at the end. We take them with the Gravity Gun. At the very end, there's another Lambda sign, with pulse rifle ammo. Then we return to that ladder and climb up.
Death Factory
Behind the barrel is a huge, high room:
Run first to the far right corner, then to the far left, and to the red booth, from which we call a platform. You can kill the soldiers with a crossbow; fortunately, arrows are everywhere. Once the platform has arrived, turn the lever again and head up. Don't forget to throw out the barrel first to avoid an explosion from an enemy bullet.
There's a ladder in the corner, then along the white pipes and along the profile to the opposite side of the room. Then back across the catwalks. Two soldiers will appear on the balcony opposite—that's where we'll go. You can get there using the same platform the soldier in the red booth called, or you can climb the ladder above and jump from there. Now, let's run for Freeman! Source
Source: hl-inside.ru