Eh, I mean yeah its a memory game but if you're a musician too, or just decent at know what a beat is, you can remember the song similar to learning a song on a real guitar. Lots of people can play guitar without looking at their instrument. Its also even easier on GH because you have only 5 buttons. Certainly a hard song, and your timing does have to be impeccable, but its not much different from the way people actually perform music.
This guy has probably played this song so many times normally, that all the movements and muscle memory are ingrained in his hands. Its certainly a little bit of a leap to go 100% blind, but having already been completely accustomed to the song, it just comes down to practicing what you already know without looking.
I wonder how mr.queeba would react to a guitarist covering a song in real life, he'd probably have a heart attack
The song is overcharted as forget on GH. Speaking from personal experience, there's a few songs on Rockband that are hard as stuff for me to play because they're complex and have lots of shreddy lines, but on real guitar, I don't have much issue playing it.