Portal 2 achievements

Portal 2

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There are a maximum of 50 Portal 2 achievements worth 1,693 (1,000)

121,493 tracked gamers have this game, 12,154 have completed it (10.00%)

Achievement Details

Preservation of Mass in Portal 2

Preservation of Mass27 (20)

Break the rules in Test Chamber 07

  • Unlocked by 66,937 tracked gamers (55% - TA Ratio = 1.34) 121,533  

Achievement Guide for Preservation of Mass

728,564 (428,760)
Achievement won on 21 Apr 11
TA Score for this game: 1,693
Posted on 21 April 11 at 03:24, Edited on 20 August 12 at 04:52
This solution has 97 positive votes and 2 negative votes. Please log in to vote.
Chapter 2 - Chamber 7

Use the third cube to block the laser and call the elevator. Now use the white platforms to bring the box to the pad, and shown in the video. Reach the exit zone, and take the hint from Glados. Shoot a Portal on any surface in the hallway, and take the cube through the other one, unlocking the achievement!

You can also get this achievement in Challenge mode, playing "The Cold Boot - Pit Flings".
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