Respect for Bill. That was impressive. I'm not an avid Chess player but to play at that speed with his obviously gifted opponent and last that long is respectable.
It would be easy for any marginally skilled chess player [1] to survive 20 moves against even the world champion. If Magnus was specifically playing to checkmate you quickly, 30 moves would be difficult and 40 moves would probably be impossible.
1: ~1500 UCSF strength