Na, I've seen it. This guy recording probably had a pretty slow pc.
Even the main menu lagged.
He probably also had a ton of other things open as well.
I tried out the demo and it was fine for me, Windows 8.1 Laptop
![Cheesy :D](http://zfgc.com/forum/Smileys/tplink/cheesy.gif)
All in all, most of their playthrough is either n64 games or just mariovania.