2 1/2 of the makers of the L4D(2) mod Dead Before Dawn went solo and created THE CORE.
This file is needed if you want to continue to play the campaign from the main menu. Valve released a new DLC for portal 2 which reads the main menu in...
You can find the updated full version of THE CORE in zip archive fomr here!
You can find the updated full version of THE CORE in this download!