After the surprise, drop down into the main chamber. Note that the turret can shoot through the grate, so be very careful. Use the stuff around the room for shielding and keep moving.
Start by using a portal to get across to the other side of the room with the button. You’re safe here because of the wall. Pushing the button drops two redirection cubes, but they’ll hit each other in mid air. Put one portal above the light bridge and create a new vertical bridge to block the first one by the spring. Make sure that both blocks land on that side, and then go back through a portal. Grab one and run over to the laser. Use it to redirect the beam into the two sirens.
Spring back over and grab the other one, and make it to the light bridge. Wait until you’re healed, and then run out and direct the beam into the turret to kill it. That makes the rest a lot easier. Just thread the needle by putting the beam through the rest of the sirens and into the receiver. It’s a straight shot.
Put a new portal above the light bridge, and then another onto the other side of the wall shielding the laser. Cross this bridge to reach the exit.
Okay, this is a bit difficult. We need to daisy chain the sirens up.
The first step is to just redirect the beam, so grab the one redirection cube on the floor and put a portal above the spot where the laser hits. Go up and redirect it into the first siren.
The next step is where it gets tricky. The only way to fling yourself around is to put one portal above the spring and drop down onto it, with another one nearby to throw you straight up into the air. Start in front of the portal, and start the cycle of hitting the spring and being throw into the air. You can then shoot another portal onto one of the various white walls to be flung to the spot you need to go. Remember to keep track of your portals. You need to swap it out so that instead of falling onto the spring again, you “fall” into the original portal and out of a launch spot.
Start by grabbing the next redirection cube. To carry a cube, you’ll need to begin the spring process again while carrying the cube. You can let go of it at the height of your jump, so that you can shoot a new portal, and still grab it before you go through the portal. It should fall at the same speed as you. Just let go, don’t toss it.
Use this to sling shot over to the one lit siren, and direct the beam over to the second siren by the starting point.
The third redirection cube is on a high and very small platform across from the exit. You need to slingshot yourself into it, using the same trick. You should be able to do it if you aim at the highest point on the wall next to it.
If all goes well, you’ll knock the cube down onto the starting area, and land there yourself. Use the beam to blow up the turrets guarding the exit, and then power up the receiver. This forms the platform we need to escape.
Repeat the slingshot trick one more time to slingshot to the exit and the elevator.
You need to direct the three beams to roughly the same point. Put one portal where the slanted beam hits, and use the redirection cubes to point the other two toward it. Use a portal on the post to direct the beams into the receiver. This is really difficult to explain, so just look at the picture.
Start by extending the light bridge by the button. Go through the portal, and hit the button in the corner to drop a cube. Start crossing the bridge you created to reach it, to get a new surprise.
Run through the hole and follow the catwalk. If you cross over to do the “final test” you’ll just get gassed, so only do it if you want the achievement.
Follow Wheatley along the bridge and keep moving until you hit the loading screen.
Keep following him until GLaDOS locks you into a room with some turrets. You can’t use portals here, so just use the metal for cover and sneak up behind each of them. Put one portal on the bit of white wall, and put another on the pillar that you can see in the gap in the wall across from it.
Drop down and keep moving. A turret will try to ambush you along the catwalk, but you can just put a portal under it to take it out. Chase after Wheatley and follow him along the catwalks to the lift to escape.
All screenshots from “Portal 2.”
This post is part of the series: Portal 2 Walkthrough - Part 1
Chell’s back, and we need to get out of the facility. For now, that means playing along with Wheatley and GLaDOS, relearning your portal skills and doing a whole lots of tests for the good of science.