It was literally from scratch. I'm in awe of the man, despite knowing that he's a brilliant man already, that shit is just crazy. He said he had a few lyrics thought out and a couple standalone riffs that he had brainstormed but obviously that's always there when actually creating something...otherwise he'd just be sitting there in the video for two hours just thinking of shit. Otherwise, nothing else was done, he made the song itself from scratch laying down every instrument, vocals, modifying it, switching stuff out in program, editing things, etc.
I really like the song a lot, even when forgetting it was done in front of our eyes in less than two hours. That is just mind boggling to me. I mean I can play fucking Smoke On The Water and the beginning to White Zombie's I Am Legend. That's it. So it's natural that I don't even get how he can do this, but the fact that it wasn't just...playing the shit and then he's done. He had the program up and was tinkering with it all the while and getting irked at the keyboard constantly disconnecting and the bass was apparently a relative POS and he had to hold back on laying down certain vocals and changing certain lyrics he didn't love due to time constraints, etc. It was a real eye opener for someone like me who knows jack shit about music in general, let alone making a song.