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Part 40
Portal

Part 40

Complete Portal Part 40 walkthrough and details on how to unlock achievements like Lab Rat and Fratricide.

By ···10 min read·Multi-source verified
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Complete Portal Part 40 walkthrough and details on how to unlock achievements like Lab Rat and Fratricide.

Walkthrough
  1. 1
    Press the button and shoot a portal at the wall above the door that is coming out.
  2. 2
    Grab the box and go through the portal near you. You should end up falling near the piston.
  3. 3
    Go through and place the box on the button.
  4. 4
    Shoot a portal at the far wall above the door and jump off of the ledge to the left.
  5. 5
    Once you land, shoot a portal at your feet to end up near the door. Go through.
  6. 6
    In here, shoot a portal at the lowest piston.
  7. 7
    Walk over to the ledge not above the water, but rather above a large pit.
  8. 8
    Shoot a portal at the ground here, then jump down through it.
  9. 9
    As you are coming out of the portal on the piston, look at the next highest piston.
  10. 10
    Shoot the portal that was in the pit (not the one on the piston) onto it.
  11. 11
    You will fall through and shoot up from the higher piston.
  12. 12
    Keep doing this, being sure to alternate portals until you reach the fourth piston, where there is no next-highest piston.
  13. 13
    Instead, look towards the area where you started this piston-jumping puzzle (the area between the lowest piston and the pit) and look up to see a wall slanted at a 45 degree angle.
  14. 14
    Shoot the portal opposite the one on the highest piston at it to be flung to a platform.
  15. 15
    Run through the doorway and into the chamberlock.
Tips
  • Your average time for this section is 55 to 59 seconds.

Achievements:

  • Lab Rat (AH01): 5 Gamer Points. "Acquire the fully powered Aperture Science Handheld Portal Device." In Test Chamber 11, grab the portal gun upgrade that allows you to shoot orange portals.
  • Fratricide (AH02): 5 Gamer Points. "Do whatever it takes to survive." Incinerate the Companion Cube in Test Chamber 17.
  • Partygoer (AH03): 5 Gamer Points. "Make the correct party escort submission position decision." After almost being baked, fling yourself up to the higher platform to continue the game.
  • Heartbreaker (AH04): 10 Gamer Points. "Complete Portal." Beat the game.
  • Terminal Velocity (AH05): 5 Gamer Points. "Fall 30,000 feet." The easiest way to do this is to shoot a portal at the ground, then a portal above it, then keep falling through for about 5 minutes. You'll get it eventually.
  • Long Jump (AH06): 5 Gamer Points. "Jump 300 feet." All this means is to move 300 feet horizontally without touching the ground. The best way to do this is go into a small hallway, then shoot a portal at the wall, and the other at the ground directly below it. Jump through either one, and you will keep falling until you move. Just wait for a little while.
  • Cupcake (AH07): 10 Gamer Points.

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