I got a message from my 10 year old nephew today on Steam saying “I finally finished Portal 2! That was hard! But so good! It was worth it”.
I congratulated him. And he proceeded to invite me to a game of Portal 2.
That didn’t compute with me for a minute. How can he be inviting me to play Portal 2 with him?
Oh right! Portal 2 had a Co-op campaign! I totally had forgotten all about it!
So I told him to hold on a minute, while I installed the game.