1. Portal 2 Achievements
2. Preservation of Mass achievement

Portal 2

899

51

4.63

42,445

2,857 (7%)

20-25h

Game action

• 31 want to boost

Sam Rattlehead

433

29

30 Jun 17

100h 31m

Preservation of Mass achievement in Portal 2

Preservation of Mass

Break the rules in Test Chamber 07

0

30 June 2017 - 1 guide

How to unlock the Preservation of Mass achievement

• Shenron129,913

  14 Aug 2015 20 Feb 2022 20 Feb 2022
  0 0 0

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