Continue forward, weaving through the webs and clearing the area of monsters along the way to the exit point. Soon, two Ant-Spiders will run out from around the corner of the steel structure, capable of striking you through the grating. So be careful when walking through the darkness (editor's note: it's best to turn on a flashlight) . Grab the barrel of explosives with the Gravity Gun and launch it at the blocked section of the road. Run straight ahead and to the left, taking cover from the insects. Clear the next obstacle with a crowbar or the gun and, after passing through it, turn left.
Deal with the three Ants in the area ahead and to the left; one may attack while you're clearing the rubble, so stay left while you do that. Run straight ahead and to the right to the ledge, then climb it and continue moving at the same pace, clearing the spider web out of your way with the Gravity Gun. As soon as the water area appears ahead, stop to avoid falling.
Note: in combat, ants, like other mobs, are easier to kill if you shoot at specific body parts (their abdomens). This only takes 1-2 pistol shots. However, this is not the case with spiders. I keep my Q and SMG hotkeyed, just in case the distance to the enemy closes to 3-5 meters. This minimizes and/or eliminates any unwanted damage from the Spider's explosion at close range. Note the healing properties of the small larvae when crushed. This may come in handy in the next chapter.
If you continue at this pace, you'll drop off the ledge, pass through the supplies, and climb up the ridge into the cover of the next area on the right before the mobs can see you. If you fail, one or more spiders will enter the area along with you and begin spitting acid. The next section of the cave will contain numerous barnacles hanging over the water, as well as antlions in the distance and one currently invisible spider. Position yourself so that the barnacles' tongues are between you and the enemy and set a trap for the monsters, enticing the ants to rush forward. Then, move away from the water's edge and await the arrival of your guests.
Two spiders will emerge from the end of the cave. They usually follow the ants, but if this doesn't happen, use the cover between the stalactites to avoid their acid spit and move into the affected area, then take out the enemies. Further ahead, there will be another stalactite with barnacles on the left and in the middle. Carefully navigate around this natural formation and continue running. Ahead, you'll encounter one Ant and a bunch of Spiders. Jump into the water, and it will protect you until you reach the surface. After dealing with the undead, another Antlion will attack in the tunnels, along with two Spiders hiding in the adjacent cave, near a very small side tunnel.
Hold off on running, recuperate, find the small tunnel on the left, and continue running until you have enough energy to reach the hole in the floor. An alarm will sound from there, and that's where the " Vort Ring " chapter begins.
Source: www.gamefaqs.com.