I don't know if any of you guys have seen this, but it's a video of John Romero playing on E4M2 of Ultimate Doom. Guess which source port he plays?
http://www.pcgamer.com/watch-john-romer ... e-of-doom/
Edit: There's actually several parts to this where he plays all of Episode 1. You can find it here: https://www.youtube.com/watch?v=ygp4-km ... xNtfWZPm5W