Portal 2 Chapter 4 Test Chamber 19

sp_a2_laser_chaining.bsp Laser Chaining

This is the twenty-eighth level of the game and is set within a half-dilapidated Test Chamber. This level requires the player to utilise advanced knowledge of the Thermal Discouragement Beam, Aerial Faith Plate and momentum in order to proceed. This level features Turrets as its main hazard.

Walkthrough

Jump down and place a portal into the room where the Beam is going. Pick up the cube on the floor and place the other portal in a spot where you can go through it.
Point the cube to the Receptacle on the other side of the chamber.
Jump down and look for a cube on the left - in the middle of the entrance ledge and the room where you jumped from. Place a portal on the ceiling above it.
Get the cube and jump back down.
Leave the cube on the white floor. Place a portal above the Aerial Faith Plate and the other below the cube to make the cube fly.
Wait for the cube to go up from the portal on the floor and while it's in the air, place the other portal on the wall in front of the Receptacle area. The cube should end up in the Receptacle area.
Repeat it with yourself.
Aim the Beam with the cube to the Receptacle in the entrance ledge and jump back down.
Look for a cube on the right side of the entrance ledge close to the roof. Place portals on the floor and above the Faith Plate.
While flying, place the other portal as close as the roof corner as you can. When you have gone through the portal, you should have knocked the cube over to the entrance ledge.
Jump down and place the same portal you just used on the ceiling of the entrance ledge. Then go through the portal on the floor.
Take out the four Turrets guarding the exit with the Beam. Then aim the Beam at the final Receptacle and jump back down.
Place the other portal above the Faith Plate and go through the one on the floor.
While you are in the air, place a portal on the same corner facing the exit and enter the chamberlock.