I used to speedrun LucasArts adventure games when I was a kid (long before YouTube or high-speed internet). I could finish Full Throttle in under 15 minutes. Now I checked on YouTube, some guy finished it in 11 minutes:
https://www.youtube.com/watch?v=Vwx_l0w_q8g

Also, Divinity: Original Sin took me and my buddy 115 hours. Guy finishes it in under 7 minutes:
https://www.youtube.com/watch?v=mryxFD3Fgew

Post speedruns that you like/blow your mind!

I don't have any vids or links, but in high school I knew a guy that could win Super Mario Brothers in 2 or 3 minutes using warps, and a guy that could beat Metroid in about 20 minutes, 15 of which was just getting energy tanks.

While both were impressive, I also thought they kind of took the fun out of it. :P Why bother playing the damn thing?

It's a different kind of fun to be had after you already finished the game and explored everything.