The "gun-recoil-knockout" guy is an idiot.
The young IPSC shooter has a serious flinching problem at 0:35 to 0:36 again at 0:54 to 0:55 and again at 1:18 to 1:19. His stance at 1:26 is extremely poor as both elbows are bent and he's not in a decent isosceles at all. He flinches again at 1:43 to 1:44 and again at 2:06 and has a giant Han Solo flinch at 2:39 and 2:40.
As far as I can see, he was never unsafe with his firearm but the way he was handling it is not at all "the right way." It is only amazing insomuch as the flinch he has developed. He's learning at least two very bad habits at a very young age and that's going to be a serious impediment to his shooting career in later years, should he pursue it. (I also heard a spectator, coach, or perhaps the range-officer say "front-sight" at least once, which is why I said at least two bad habits, if not more.)
I thought the "i-Gun" was pretty funny. Apparently there really is "an app for everything."