TarionzCousin
Second Most Angelic Devil Ever
I won't be impressed until he runs up an elephant and kills it singlehandedly. 

Puts more credence into 1e rate of fire.
Yes. He's using a 35lb test bow similar to what a girl scout or boy scout would use. And he doesn't even draw back the bow fully to his chin, but pulls it about 3/4 of the way.
I'd guess about 80 feet per second, or less than half the speed you'd expect with a hunting or war bow. Hense the ability to perform the tricks.
So, as far as myths go...
1) It is true that back quivers are ahistorical for Europe. They are not ahistorical for North America, Africa, or Japan - and it's not like Japan didn't have refined archery arts. It's likely that Hollywood got the notion that quivers were worn on the back because the most recent USA experience with real archers was in the Native American wars. It's really weird don't you think how he can discipline his body in every way EXCEPT to keep his posture upright enough to keep his arrows in a quiver. Native American and African hunters managed just fine.
2) While it is true that the Hun archery techniques that he's most fascinated with were lost as a result of a political situation, it's not generally true that all ancient archery was lost just because 'gunpowder'. Afterall, archery was widespread in many areas into the 19th century, and is still practiced in some areas today.
3) It's not true in general that ancient archers were highly mobile warriors. Horse archers, sure, but we aren't talking about horse archery. Those same pictures showing features like holding arrows in your bow or draw hand, also often show those same archers with arrows arranged around their feet. The vast majority of archers fought in semi-static positions, sometimes accompanied with a shield bearer to defend them. Skirmishing with a bow would have a variety of disadvantages and light skirmishers tend to disappear overtime anyway, probably because they aren't that effective against disciplined troops.
4) He's not actually that accurate. The target archers he disparages shoot at penny sized targets at 20 yards and missing by more than about a quarter's distance is considered a bad shot. At 60 yards, they shoot at 9cm targets. At equivalent ranges he hits somewhere on a dinner plate and somewhere on a 2x1m target, most of the time. Most of his shots are from 8 yard or so away, if that. And the hitting moving targets isn't that impressive either. The top trick shooters routinely shoot penny sized targets that are falling, and they've been doing it in front of live audiences for years. Since he's only doing it on a video, we don't know how much Jackie Chan magic is involved here. He's clearly highly skilled, but we don't know how many takes were required to produce the perfect shots. He starts touring and doing this for live audiences for a few years, and then I'll believe.
5) The sort of rate of fire he's using has only limited battle field utility - mostly I would think if you were on a horse and riding by a formation of infantry. But as infantry, your burst rate of fire is far less important than your sustained rate of fire. Assuming you are drawing a 75lb to 110lb bow, firing a shot every half second - even if it were possible - would leave you exhausted in short order. Archers fired about every 10 seconds not just to get good aim and make sure their shot counted, but because firing faster is equivalent to sprinting in terms of exertion you are doing. If you are trying to fire only every 6-10 seconds anyway, a lot of his economy of motion is wasted.
All that said, until he came along, the top Hun archery recreationists were firing with arrows in the bow hand on the left side of the bow at about 1/3rd the rate he fires. At the time, it was generally believed that a lot of the historical descriptions of rate of fire were purely legendary. Now, any halfway decent kid copying his techniques and practicing for a few weeks can recreate tricks that were believed by experts to be impossible just a few years ago. He deserves a lot of credit for training and reinventing a lot of techniques no one was really paying attention to.
someone should make a subclass based on this dude
And he puts them through chain armour, so yeah, I'm impressed.
I make my points about the questionable utility of this method, against an armoured opponent, below.
His achievements are far from trivial, but are made so by the overblown claims.
Puts more credence into 1e rate of fire.