Yes, the comic is official, it is originally hosted on Portal 2's official site:
http://www.thinkwithportals.com/comic/
Yes, the comic is official, it is originally hosted on Portal 2's official site:
http://www.thinkwithportals.com/comic/
I was just about to post that!! Guess I was too slow... That's the full comic. My earlier link to IGN was only the first half