This is a collection of all the publicly released maps from past and future contests held by thinking.withportals.com, most of this maps you can find in the portal 2 workshop, but some others that might be previously lost to time or difficult to reach, are being/will be made available to the general public via this pack.
This competition was all about visuals. Specifically, short maps with really good visuals. No puzzles where required, but participants could include if they want.
In order to restore your portal 2 installation to it's original state, just delete/remove the "portal2_dlc3" from your C:\Program Files (x86)\Steam\steamapps\common\Portal 2 folder.