Articles about Valve games.
Pages in category "Valve"
“ How to Obtain: Complete the first Hard Light Bridge test In Depth Explanation.
Portal 2:Bridge Over Troubling Water
“ How to Obtain: Place a cube on a button without touching the cube. In Depth Explanation.
Portal 2:Drop Box
“ How to Obtain: Complete the same test twice. This achievement/trophy is unlocked through story...
Portal 2:Dual Pit Experiment