Chapter 15. Xen (Credits) [Black Mesa]
We exit the cave. On the horizon are tiny islands hanging in space. We need to reach the island with the teleport tower.
We follow the path to the left. On the way is the dead body of a researcher; you can collect ammunition from such bodies. A purple cloud is floating nearby - a protozoan (1); they serve as secret items; you need to shoot 64 of these clouds in total during the game. A little further is the second body and a protozoan (2).
We press the lever to lower the springboard. Here is a training ground for double jumps. There is a barnacle hanging in the path; we shoot it on the ceiling. If we fall, we can climb up the path. Below, by the water, there is a protozoan (3). Ignore the outdated Ctrl+Space prompt, press the spacebar, and then hold it down a second time. The jump pack will take you across the chasm.
Second ramp. There are ammo on the right behind the barnacles. Jump to the island with blue healing fluid. Further on is a broken ramp. You can jump to the side island on the left, where you'll find armor and a houndeye monster.
Third ramp. Up ahead, on the large island, a whole herd of four-legged houndeye monsters will attack. Protozoa are flying above the rocks to the right (4, 5).
Inside the cave, there are ichthyosaurs in the water, so you need to lower the ramp and jump across the islands. Halfway along, you can jump to a dead-end island on the right; there's a crossbow and a headcrab there. Reach the entrance to the human expedition camp. Connect the cable on the right and press the button to the left of the door.
There are headcrabs and zombies in the rooms; collect ammo from the shelves. In the second room, climb the fallen shelves counterclockwise. In the large room, there's an Earth generator; power it with the alien yellow crystal, which will open the door with an electronic lock.
On the right side of the excavation site, take the yellow crystal, insert it into the alien generator, and connect the cable. On the left, connect the cable to the Earth generator; it will charge, allowing us to open the door on the left.
We'll return to the central hall, but now the door on the right will be open, and a zombie will emerge from it. In the hallway, take the plug from the empty red battery and insert it into the nearby charged blue battery to unlock the doors. We'll leave the camp.
At the exit, there's a healing pool on the left. Collect explosives from the shelves ahead on the right. Ahead, shoot the explosive plants. Grab a crystal from the crates above and insert it into the Zen Generator. Disconnect the cable above and connect it to the Earth Battery on the crate below, opening the door.
Two protozoans (6,7) are flying at the entrance to the forest. There's ammo on the right, protected by a tentacle plant; we can quickly run under it. Climb the elevated area on the left and fly to the large leaves in the center. Houndeyes will attack on the way up. At the top, before reaching the cave entrance, look left to see a protozoan (8) flying there.
Inside the cave is water with ichthyosaurs; jump across the large lilies. On the shore, there are Bullsquid monsters spitting acid. Three Protozoa (9, 10, 11) are flying above the water.
This will take us back to the lake with the crocodiles, but now we can climb higher along the leaves. At the top, we'll encounter a Houndeye and a healing pool. In the upper cave, go right and shoot the second growth. On the left, make a long jump to the leaf.
We'll emerge at the river. Three Protozoa (12, 13, 14) are flying to the right of the entrance. We'll be attacked by red Houndeyes, which run up and explode. Before the rocks, go right and connect the cable to the Zen Generator. All that's left is to bring the crystal to it. We go right, look inside the tree, and shoot the red growth at the top of the tree near the ceiling. Three protozoa (15, 16, 17) are flying near the growth.
We go into the opened passage on the left. At the top, on the left, shoot the red growth, jump into the hole under the leaf, and fly up on the spring. We blow up the plants, take the crystal, and return to the generator with it. The portal will turn on. (If we are carrying an item, first teleport it, wait a second, and teleport ourselves.)
We will appear a little higher. We take the ammo. We press the lever; there is a spring on the pulled-in island. We fly higher, and follow the stem above the previous place. Ahead, we shoot the first growth. Standing on the edge, turn right, shoot the second growth. We jump inside the opened cave.
Inside the tree, jump across two springs, collect ammo, and kill zombies. We'll come to a large tree; you need to remove all the growths here. (If you're carrying an item, leave it in the center.) You can jump down a bit lower; there's an underbarrel grenade there.
1. Left growth. The tunnel has many balconies with crocodile monsters on them; it's best to shoot them from afar with a scoped crossbow. Climb up the spring and jump to the lower central balcony. You'll find a red blob at the very top of the path.
2. Central growth. Climb the spring and jump to the central tree, onto the right branch with a body. Continue along the narrow path, shooting the barnacles on the ceiling along the way. When we reach a dead end, turn around and jump to the next path. At the top, we'll fall into a pit with explosive plants along with the snarks. Go out and blow them up.
3. Right growth. There are laser mines in the cave; you can't shoot them, otherwise the entire tunnel will explode. Crawl under the lasers. Shoot the last growth. You can recover in the healing pool. (Grab the item from the center, if you were carrying it with you.) Exit the cave near the pool.
At the exit, jump over a large chasm. Eight protozoans (18-25) are flying in the air. To the right, across the river, there are ammo, under a claw. Go up the river. We'll see an armored houndeye kill a crocodile; we fight it.
After exiting the cave, we'll see a protozoan (26) in the air. All types of houndeyes are on the way. There's a dead end to the left where a body lies. A large island is visible in the distance, and a protozoan (27) is flying in the air to the left. Crystals are hanging on the rocks above; we'll see that they turn ordinary houndeyes into kamikazes. We shoot both the monsters and the hanging crystals.
In the next river, there's a healing crystal in a dead end to the left above. We'll enter the gorge with birds in the sky. Press the crystal below. Jump across the water to the portal behind the waterfall. Climb the hill on the left, where the second crystal is. Enter the second portal and move a little higher. We'll shoot the houndeyes along the path. We'll go up the river.
In the cave, at the crossroads, we go right. We'll reach a clearing with flowers. Jump across the river, climb the cliffs on the left, and jump onto a leaf ahead to bypass the thickets on the river. Just beyond the thickets, three protozoa (28, 29, 30) are flying. Jump into a deep hole and fall into the pond.
Four protozoa (31-34) are flying above the water near the waterfall. In the underground cave, we'll see water barnacles; they grab objects on the surface and drag them to the bottom. Jump across the lilies, avoiding the barnacles' claws. To the right of the second lily, there's a bank with some ammo.
Don't linger on the lilies for long; they slowly sink underwater. We'll reach the shore. Ahead, we'll see a large island. Carefully descend. A weapons capsule teleports directly in front of us, and a healing pool is nearby.
Dive into the enemy-free pond, shoot the red plants at the bottom with your crossbow, and continue fighting your way through, but ichthyosaurs will emerge. Barnacle roots stand in the way; swim through them from the near-right corner to the far-left corner. Resurface, blast the barnacles on the ceiling, and jump over the thickets. At the end of the path is a healing pool. Jump into the cave
There are several paths leading to the island ahead. There are ammo at the beginning, and many Houndeyes along the way. At the very beginning, jump onto the central path, go down to the left, and you'll see a protozoan (36) under the path. At the top right, return along the path to the beginning and enter the upper dead-end cave. Inside, there's a crocodile, ammo, and a protozoan (37).
At the end of the paths, crouch and crawl between the roots. Climb up the only narrow path. There's a capsule, ammo, and a healing pool along the way. Shoot the yellow crystals on the ceiling.
Enter the portal control room and press the green button. (If you're carrying an item, you can leave it in the room.) In the side room, disconnect the cable, jump down to the basement, jump over the chasm, and go up the elevator.
1 beam. Connect the cable to the upper and central connectors. The door on the left will open, behind which we take the crystal and take it to the connector on the ceiling. Press the green button and jump down the green hatch on the right.
Further along the path is a force field; turn around and go to the upper path. We'll go around the field through the cave, and on the other side, shoot the bombs on the ceiling to deactivate the crystal. We'll go back and jump over the deactivated field. We'll go through the cave with lasers.
Beam 2. The control room is overgrown with bombs; shooting is prohibited, so jump on the bombs. There are bags of explosives in the capsule ahead. There's a cable hanging on the wall; disconnect it on both sides, take it, and place it in the side dead end. This will activate the protective field. Exit through the door, throw the explosives, hide behind the door, and detonate them. Then, leave the explosives in the dead end, exit, close the doors, and detonate them. After two explosions, you can plug the top cable into the left socket. Grab the yellow crystal in the dead end and take it to the empty generator. This will activate the second laser.
Beam 3. Follow the path with yellow lasers and houndeyes; at the end is a healing crystal. In the right tunnel, jump onto the yellow crossbars to reach the last room. In the center, near the yellow pipes, grab the first cable, take it to the side corridor, and insert it into the sockets on the right and in the center. A hatch in the floor will open in the center; jump down.
Climb up. Disconnect the cable in the hatch and insert the crystal into the generator. The main control panel will turn on; press the button, and a portal will open in the center of the lasers. (If you're carrying an item, take it with you from the room.) Exit to the left and enter the cave, teleporting to Gonarch's lair.