This is a Community-Made Mod for Portal 2. It plays before the events of Portal 2 in the dead and decaying Aperture facility. 40 brand new puzzles in it. You do need to own Portal 2 to play this. And it has been released for free.
store.steampowered.com
Portal: Revolution on Steam
The Portal Mod you've been waiting for. Delve into a new story with original characters, spanning over 8 hours of gameplay and featuring over 40 new challenging test chambers which make use of new mechanics.
