Portal 2 Chapter 1 Test Chambers 3 & 4

These chambers form the fourth level of the game, and take place within two separate dilapidated Test Chambers. The two Test Chambers introduce the concept of using multiple Weighted Storage Cubes in conjunction with intermediate Portals, as well as utilising the Aperture Science Handheld Portal Device to obtain objects that would otherwise be inaccessible. These two Chambers correspond to Test Chambers 04 and 05 from the original Portal.

Walkthrough
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Chamber 03

 * When entering the chamber, observe the Weighted Storage Cube falling into the pit. Either fire a portal below the cube, or jump down and then fire a portal at a wall and then carry it through, to bring it to the upper level.
 * Place the cube on the Heavy Duty Super-Colliding Super Button; proceed through the door into chamber 04.

Chamber 04
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 * Observe the orange portal on the platform across the room; place a portal and walk on to said platform.
 * Place a portal on the opposite platform; it is now possible to acquire the cube through the orange portal. Place the cube on one of the buttons by the door.
 * Opposite the door will be a pit containing a cube; fire a portal below the cube at the bottom of the pit to place it on the platform with the orange portal. Follow the cube through this portal or through a new portal on your current tier, whichever is most convenient, and place the cube on the remaining button and walk through the door.
 * Look up to observe an orange portal through the glass; place a portal on one of the surrounding walls and walk through it to land on top of the glass.
 * Turn around and walk through the destroyed section of wall to reach the Chamberlock. Inside this wall section is a staircase that leads to a Rat Man den.

Music
Short sample from Offering by Larry Stephens [from 1:22 in track]

Trivia

 * In the original Portal, these chambers are separated by an elevator, but in Portal 2, this is retconned to Chamber 4's entrance being merged with Chamber 3's exit.

Challenge Mode

 * Map name: sp_a1_intro4.bsp
 * World record: 21.31 by AngerySnek
 * Portals: 0
 * CM (Challenge Mode) Available: Yes