If you were tasked with showing someone what a ‘video game’ was, and they had no prior experience with the medium, I think Portal 2 might be the best place to start. A game that does so much with a simple concept, just continues to reiterate, expand, reiterate again. Wrapped in a highly engaging story, a great balance of horror and comedy. It’s a pure game. I think there is something to be said that Valve--at the absolute peak of their power as a developer--said what they wanted to say with regards to single player gaming in 2011, and didn’t take another stab at that type of game for another 9 years.