While I do not doubt the authenticity of this video, I am a bit more a critic than most people appear to be.
As a modern barebow archer myself (not that crazy pimped up shit with scopes 'n stuff, ffs) I find it very hard to believe that you can hit your target as accurately as he does, consistently when you do not anchor on a set point. For the non-archers, anchoring is where you place the hand with which you are pulling the string in a set position on or near your face to keep a consistent shot. Mind you, this is for target shooting. I am very well capable of hitting an inch wide target at 25 metres this way. I am, though, 100% sure the man in the video can't. At least not as consistent as I.
Though I have to keep in mind that he is not shooting target, so the accuracy isn't that much of a problem with him, as long as he hits the target in general. When warring, one does not need to pick the opponent's eye to pierce: hitting either one or the bit in between will do just fine.
And while it is true he can hit that all with his own bow, I very much doubt that his wil come over 45, perhaps 50 pound in the draw. One should also keep in mind that his bow is most definitely not hand-crafted in the way they did it in the middle ages, so his bow will naturally be more accurate. Same goes for his arrows.
In short: I doubt that it is as simple and straight-forward as is stated in the video, but I can't but admire this man's skill and the way he ridicules recurve and compound archers, whose sole problem nowadays is finding suitable virus protection software for their bows.
I think you can best compare his archery and mine with modern warfare as this man being the infantryman with a regular rifle and my style being the sniper, although in this case the skill level of either one is just as large as the other, because I am very curious how this man will perform on the longer distances (50, 70 and 90 metres)
Oh, and may I just add that back-quivers aren't used by any sensible modern archer: they're the most bithcy piece of equipment. Archers use side-quivers instead.