Okay, one or two things I feel need to be pointed out.
First is that I watched the youtube video - you DO understand the 12 or so minutes it took him to create that digital work is sped up right? He didn't make that work in 12 minutes. It's merely a 12 minute long video.
Second - The first thing he did in the painting process was remove all the white from that canvas.
Third - I seriously doubt he just started painting this. If he DID just go right into working on the artwork, he's made a TON of artwork before - so he knows what he wants the end product to look like, and he knows how to start. Chances are he's also looked at thousands of reference photo's, and has made even more sketches.
There's a lot going on.
Also, I agree about the cropping - I'm not happy with the final composition - but at the same time it stokes the imagination and makes me want to look at the rest of his work.
Doctors heal you, Artists immortalize you.
"Those who can, do. Those who can't, teach" - bullshit.
The usual staples for anatomy: