- 1. As the group follows the sewage flow, there will be a few enemy encounters, including Grabbers, tentacle-like creatures that try to grab Nathan and bring him to them so they could kill him off. Shoot any Grabbers you see in their heads (one hit with the Plasma Cutter does the trick).
- 2. Text Log #1: After killing the first Grabber, the group goes down the tunnel. Lexine gasps at a falling object, and then Nathan turns towards a locked door up on a platform. Shoot the air vent above the lock door and grab the Text Log before he moves on.
- 3. When Weller talks about the exits being locked down there is a Line Gun on the platform to the right. The Line Gun is to the left of the locked door.
- 4. The path eventually forks, though both routes will take you to the center area for a big brawl. If you went left, there will be Grabbers, Exploders, and Slashers, while right has you fighting more Enhanced Slashers. There's plenty of Green Canisters to open here; it'll be helpful to hurl them into baddies using Kinesis for quick kills.
- 5. Both paths will end up in a sewer tunnel with loads of Exploders and Slashers charging ahead while "Lurkers" (baby-like creatures with tentacles) are flinging projectiles at you from the above catwalks. Firing them back with Kinesis is advised.
- 6. Nathan can grab an Arc Wielder after the fight; do so if you are low on your primary weapon.
- 1. After the cutscene of the worker getting killed, wipe out the Enhanced Slashers and the Infectors. Enhanced Slashers can take a lot of ammo before they go down, so try one-hit killing them with a Line Gun blast to the shoulders. Nathan will Free Look afterward, allowing you to blast open Green Canisters for supplies.
- 2. Lexine will fall into the water and be swept away, and the group must find her. Watch out for enemies as you progress. After killing the first group, you can grab a P-Sec Pistol on the platform above and to your left, where a Lurker was attacking.
- 3. Weapon Upgrade #1: After the catwalk with the P-Sec Pistol are two platforms to your right with two locked doors (a lone Leecher attacks right before it). Shoot the air vent above, before the group goes left into the dead-end.
- 4. Weapon Upgrade #2: Yet another Weapon Upgrade hidden in an air vent, almost right after getting Weapon Upgrade #1; this time it's in an air vent above the platform with the propped-up headless corpse that startles Eckhardt.
- 5. The path continues into a dead end, then back towards a catwalk the group must climb. There will be two groups of Enhanced Slashers and Grabbers, as well as Female Slashers and Lurkers on catwalks. Headshot these Females for an instant kill and remember to hurl away incoming projectiles with Kinesis.
- 6. After killing the second group of enemies, Nathan and co. will enter a new area. You can grab a Force Gun when Nathan turns right after entering.
- 7. The room is flooded with gas; you must quickly win a Hacking Mini-game before the gas takes effect. Afterward, Nathan and co. will drop down.
- 8. Audio Log #1: You can see the Audio Log underneath the catwalk mesh after winning the Hacking Mini-game; you'll be able to grab it after Nathan drops down into the water and turns to face it.
- 9. Afterward, Nathan and co. continue. A Lurker will appear and, despite it actually being an illusion, you must kill it quickly anyway before it can pile on damage.
- 10. Weapon Upgrade #3: It's in the air vent above the Lurker hallucination. Shoot the Lurker, then the vent, then the Lurker, then grab the upgrade, then kill the Lurker.
- 11. Keep going and you'll hit a fork. Doesn't matter which way you go either as the left path is a dead-end anyway, and the group will eventually go route.
- 12. Weapon Upgrade #4: As usual, shoot the air vent above the elevated platform, in this case, the one before the platform holding the Contact Beam.
- 13. As the group travels along the right-hand route, Nathan will eventually spot a Contact Beam after cutting through some growth; you can replace the Line Gun with this if you like although the other will be useful against the incoming boss.
- 14. Ahead is another Lurker and Slasher ambush. As always, use the Lurker projectiles against the enemies.
- 15. Text Log #2: Grab the Text Log on the console behind this Lurker.
- 16. Text Log #3: Past the platform with Text Log #2 is another platform with a load of Green Containers. As always, shoot the air vent above it.
- 1. Further ahead you will reach a vast room, with a new character above you, Karen. She will flee when a boss creature attacks, called "The Urchin".
- 2. For the first phase, the player can disrupt these attacks by shooting at the yellow orbs in either tentacle, a task best suited for rapid-firing, instant-hit weapons such as the P-Sec Pistol or the Pulse Rifle, After a certain number of swings, the player will then move to a raised ventilation shaft on either side of the Urchin and enter free-look mode; when this happens, the player needs to use Stasis on the fan, whereupon they will head into the tunnel and the Urchin will try to grab them, only to have its tentacle severed when the fan starts up again, destroying that fan.
- 3. After its first set of primary tentacles has been severed, its secondary set will be deployed. Explosive barrels will now begin to emerge from under the water. The player must use Kinesis to grab these and hurl them at the arms when the yellow orbs are exposed, blowing the tentacles apart. Only a single hit with a barrel is needed to destroy an arm, and it is best to wait until an arm is lunging in to grab the player. If the player is grabbed, though, they will be drawn to a now-exposed mouth, which will repeatedly bite the player until they either die or shoot the mouth sufficiently to persuade the Urchin to release them.
- 4. Weapon Upgrade #5: It's on the catwalk where the right-hand fan is. Grab it during the Free Look before dealing with the fan.
- 5. When the secondary set of tentacles has been destroyed, the main body of the Urchin will surface and it will begin disgorging explosive pods, either singularly or in batteries of three. The player may use Kinesis to grab these pods and throw them at the knot of yellow cartilage rapidly swinging back and forth in front of the Urchin's body, or simply open fire with their weapons. Approximately three or more direct hits will destroy the Urchin. Once the Urchin is killed, the level will end.