Its an earlier build of the game. The crash was a result of him trying to load an earlier build save into a newer build. Always tricky that.
Just join the chat on the Civfanatics site and discuss the video with your fellow fanatics. Its right in the middle of the link bar at the top of each page.
This is hilarious: They talk about how great Steam Cloud is and then everything freezes. Haha.
Overheated graphics card? That doesn't sound very promising.