[Necromancer]

Guarding The Core

After a bit more intervention, you should be able to finally reach the core, where Alyx will summon an elevator and send you in to do your bit for god and country. If you recall your adventures in Black Mesa, this isn’t the first time Gordon Freeman has had to deal with a faulty core, although this may be the first time he’s ever had to deal with alien technology on this scale. Can he solve the magical mystery and return the world to a state of idyllic beauty? We’ll see...

When you reach the core, suck in energy balls and destroy the stalkers on the far platforms near your position. When both of them are dead, start plugging in balls into the receptacles here; there are three in all, and when all are filled, you’ll be able to move all the way around to the far end of the platform and throw a switch there to reposition the platforms to allow you access to the central spire. Climb the ladder there, then move back across the walkway to find the first of three control rooms. You’ll need to charge up each control room to enable all three restraining fields; doing so will cause the reactor core to come back in line and hopefully stay stable enough to give you and Alyx time to find a way out of the city.

First Room

The first room is easy enough to take out. Just enter, kill the soldiers, then return to the core reactor room and grab an energy ball. Plugging it into the receptacle in the first room will get the restrictor field started there, and open up a door allowing you to move on. Be ready for more soldiers, though.

Second Room

After you’re done with the first room, move down the nearby hallway and gravgun the hatch leading to the energy conduit to move through. The energy balls here will hurt if they impact you, so be sure to not give them the opportunity; either jump over the low-lying ones or dodge the higher ones. Kill the soldiers in the hall nearby, then return to the core. You’ll need to drop the forcefield by snatching the energy ball out of the energy beam nearby.

To get past the core, you’ll need to time your move on the small, melted ledge so that it coincides with the core’s inward movement. It pulses in and out, and if you happen to get caught on the ledge when the core’s expanding, it’ll instantly kill you. So wait until it’s retracting, then sprint past it as quickly as possible.

The second room is the same as the first; grab an energy ball and place it in the receptacle to activate it. Take the elevator up to the third room afterwards.

Third Room

After riding the elevator here, you have to hop onto one of the three spinning blades that make up the uppermost restraining field for the core. After you’re atop one of them, pull the manhacks that attack you in with your gravity gun, then shoot them into the energy beam atop the core to instantly kill them. Jump onto the far platform when you’ve rotated to it to move on.

From here, make your way through the small corridors until you reach another energy conduit, full of nuclear happy fun balls. All of them are jump-overable, but they’ll be coming in rapid succession, so they’re going to be difficult to dodge. Do your best to make your way down the conduit as best you can until you reach the third control room.

To activate this final containment field, grab a ball and throw it into the receptacle. Since this is the last of three activation areas, though, something is bound to go wrong, and indeed it does, as the containment device fails to initialize. It’s under-powered, is the problem, so drop down behind the machine that’s risen up from the ground and look at the three devices here. In order to activate them, you have to find the crack in the ceiling, suck down balls from there, then chuck them at the energy receptacle. Just be sure to hit the third battery while you’re standing on the ramp underneath the containment room. If you get stuck down here because the ramp raised while you weren’t on it, just suck one of the balls back out of the battery to lower it again.

Heading Out

With all three of the containment fields active, the core should be contained - for the moment. Return to Alyx through the door nearby to learn of something new in the air - some kind of Combine secret master plan. Time to get back to Dr. Vance to see if he can make heads or tails of it.

When you reach the bottom of the elevator here, move around into the room where the rollerballs appear, then have Alyx convert both of them into friendlies. They’ll kill off the Combine troopers for you, allowing you to make it into the train nearby. Of course, train rides rarely go smoothly, so when the whole thing crashes, crawl back to Alyx’s position and pull the stalker off of her with your grav gun in order to keep moving. When you’re outside the train, just crawl underneath the piece of rubble nearby to move on to the next chapter.