This Vortal Coil

The second chapter in Half-Life 2: Episode Two, This Vortal Coil concerns Gordon Freeman and the Vortigaunt's attempts to save Alyx Vance's life by venturing deep into an Antlion nest.

Walkthrough
Fall through the hole to be greeted by Griggs and Sheckley. Before you go talk to the Vortigaunt, stock up on the plentiful supplies dotting this place, and get a good feel for the area. Go talk to the Vort, and afterwards the two humans will fill you in on what's happening.

Equip your shotgun! Imagine each element at your disposal as a single resource: Griggs and Sheckley is one, each of the turrets is another, and then there's you. Each resource can protect one tunnel with one light on its own, but no more than that. The hopper mines aren't that useful, they'll take out the first Antlion in a wave and that'll be it (you can get an easy Achievement by using them though). You may like to pull a couple onto the ramp leading to the Vortigaunt as a safety clause. Things will start easy and get progressively more difficult. Keep pulling the turrets around to protect the tunnels, keep going back to the ammo crates. Around the seventh wave the turrets will blow; this is the hardest part. In the next wave more Vortigaunts arrive, and then after that about a million Antlions will appear. This bit's pretty spectacular but not actually that hard, as the Vortigaunts are extremely good! Equip up again and then head after your new companion.

The Vortigaunt can activate motors, so in this level if you see a motor ahead you know you've got to get the Vortigaunt to it somehow. It will follow you now as you head into the passage to the right. Open up the "grim penata" on the left. Keep on going until you come out into an open area. There's a group of Antlions ahead to the left which the Vort will zap; take advantage and blast them while they're struggling. More will appear, keep moving, keep shooting, make sure to get them when they're immobilized. Once they're done walk on into another open area with a winding, narrow path. Move, shoot, don't fall into the chasm. Keep going. A Worker will try and lead you into a trap as the passageway narrows and twists right and left. Once you're done drop through the hole at the end.

Get the Zombies' attention here first, work with the Vort to take them down and then punt open the door. Be careful here, there's two Fast Zombies in the room to the left who are playing dead. In the next room, pick up the heavy scrap and a barrel and place it in the lift before getting in yourself. This should be enough to get you to the bottom. To the right a Zombie will appear, as well as a Zombine protecting some supply crates. Head into the next room to examine your next puzzle. Go around towards the control panel, beware the Zombine. Activate the lift, then go back and lift out the scrap at the bottom. Deactivate the lift, then Grav as much scrap and barrels onto it as you can. Activate the lift again, step on it, punt some of the weight off it and up you go. The Vort will be blasting Zombies at the top, help him and then Use the valve to let him through. Lead him to the motor and through you go.

Careful with the supply crate mine cart here. Once you take two crates off, it will tumble into the abyss. Quick work with the Grav Gun should avail you some if not all of them. Head onwards towards the boarded up shaft. Go up to it and then quickly away again, as Zombies will send a cart smashing through it. Workers and Zombies will have a fight now; once the Zombies are dead chuck a grenade up onto the Workers' platform. Head upwards and right. Climb up the ladder and through into a small room. Punt the cement mixer type thing forwards, careful of the Zombie's grenade. Drop down on the cart, enjoy the ride. Climb up the ladder, beware tumbling debris. Before you head through the hole on the left there's some supplies to be had at the far end of the tracks. Head down the narrow pathway, have a look at what's waiting for you on the left. Keep going along and around. The Antlions will ignore you until you jump down and attack them, so pick a couple off before you do.

This bit's basically two sieges, one after the other. Once you get to the Thumper, lots of Antlions and Zombies will appear, and they're mostly interested in you. The Thumper won't protect you against Zombies or Workers! Once they're all dead, climb up the ladder near the Thumper, pick up the ammo and health, head along the boardway to get some hopper mines. Set them (not near the Thumper), make sure you're all geared up, and then head to the lift button on the wall opposite to where you came from. Once you press it yet more Zombies and Antlions will appear. Fall back on the Thumper and fight them off until the lift arrives, quickly get on and send it up again. Don't worry about the Vort, he's having a great time.

Once you've reunited, ammo/health up and head on and left. Drop down into the large shaft. Head forwards, punt the wood holding the grating up out of the way. Turn right at the t-junction, punt the wood holding the grating again but this time step back quickly. Trudge onwards until you get to a room with an elevator shaft. Jump from the entrance to the large vent below, beware the small metal overhang which will break as you land on it. Crawl down the vent. Punt the bench out of the fan, and then run towards the fan to prevent being blasted outwards. Once it breaks, use the Grav Gun to punt the fan around clockwise until the gap is facing downwards and you can crawl through. Head left at the end, drop down the hole.

Kersplash. Beware the Barnacles and head underwater to the far end of the stalagmites, there's an underwater passage blocked by bodies and Grub web. Whack your way through and then beach at the yellowy tunnel. Crawl your way through. Beware the Worker which will spit acid at you as you clamber out. He's got two friends as well. Once you're finished here head onwards, the exit is a short drop on the far right from the entrance hole.

This is where things get tricky. Fall down and wait for the Guardian to bash into the rocks, and then sprint past whilst it's recovering. Keep running until you see a hole on your left, duck in quick. This sets the tone for the rest of this bit. Crawl through, pick up the health, head down and whack open the opening. You want to be going the opposite way the Guardian goes. Leg it to the next hole along. Crawl through to the next opening, pick up the battery across the way using the Grav Gun. Again, get out, sprint in the opposite direction to the Guardian to the next hole. Pick up what's there, drop down, whack open the web. This is the worst bit. You need to be heading through the passageway its guarding, not the way to the left. It will first punt rocks at you. Make sure to grab one with the Grav Gun. When it charges, head in the opposite way it's coming from backwards. When it's starting to gain on you, punt the rock at it. This should stun it and theoretically give you enough time to turn and sprint to the next hole, on the left. Crawl in and down and to the next hole. Sprint left to the next hole, which is on your left and covered by web. If you crawl through here, you'll end up back where you came from. Instead, back out of this hole once the Guardian's retreated, and continue sprinting left. You'll come to a boarded up mine shaft on your right. Blast it open as quickly as you can and duck inside, and then back into the corner. Phew!

Once the floor has been broken, head along into the next chamber. There's plenty of grim penatas to be had here, but there is also a Headcrab, an unpinned grenade and a Poison Headcrab guarding them. Head over to the lift shaft on the left to hear the Vort calling you. Go to the scrapped engine opposite the lift shaft and grab a big cog off it, and head back to the lift engine. Two barnacles will try to stop you putting the cog onto the lift engine. Once you have activated it, press the call lift and the Vortigaunt will descend. He will head down and activate the motor. Go inside, enjoy the show, and then travel all the way back with the Vortigaunt to Alyx. When the Vortiguant instructs stand opposite him as they begin the ritual. Doctor Freeeeeeman...once it's all done make sure to stock up on the supplies here and then get back into the lift with Alyx and the Vort.

Head onwards. Careful of the Guardian as it smashes through on the right, it can hurt you here. Head on up and out. Have a zoomed look at the bridge, and then punt your way out to the left. Head downwards and then left. You need to run quickly to each Thumper, the Antlions that spawn here are infinite. Make sure to get the supplies that are scattered around here, you'll definitely need them. At the third thumper, head outwards towards the mine rail. The Guardian will smash through from the right, and then after a short time a Guard will appear from the opposite cave. You need to kill both. Dodge and weave, use the explosives littering the place, head back to the third thumper if you need a reprieve (although be warned the Guards will punt things at you if you do this).

Once this is done, the Vort will activate the motor near the lift. Head through and up the ladder, turn right along the ledge. Be careful of the landslides here, and of the Poison Headcrab. Turn left along the ledge, don't step on the boards that lead across as these break. Edge onto the lift, grab the spar blocking the trapdoor out of the way, and then into the lift. Grab the pick jamming the lever. Wait for Alyx and the Vort to step in, then press the button. Head along the passageway, turn left and jump down to end the chapter.