The Xen teleporter Gordon goes through transports him into the lair of Gonarch, the Queen of the Headcrabs. Gordon faces off against Gonarch throughout several sections of the lair until the Queen is cornered in a small room. Once Gonarch is defeated, her body explodes and opens the ground below her; revealing a teleporter that will send Gordon to the next area of Xen.
This Chapter contains examples of:
- Boss Battle: Gordon faces off against Gonarch, the Queen of the Headcrabs.
- Sequence Breaking: In the final room where you face off against Gonarch for the last time, it's possible to blow open the floor with enough explosive weapons instead of it opening up when the defeated Gonarch explodes. This allows the player to take the opened floor's teleporter to the "Interloper" level before Gonarch's been fully defeated.
- Sidetrack Bonus:
- The first map has a small hidden island with a healing pool that's away from the area that you fight Gonarch.
- The second map has an area below where you fight Gonarch where you can find supplies and a hidden healing pool.
- Unique Enemy: The baby headcrabs, periodically spawned by Gonarch, are only encountered here. Their almost-microscopic size makes it hard to just shoot them, so the player must use explosives to take them out.
- When Trees Attack: Some Xen fauna will wallop Gordon with their whip-like branches.
