Inability to follow simple directions, is my guess. That looks like the performance you get with a badly calibrated audio pipeline. Either he did not calibrate at the same or higher volume than he plays at, he moved the console and Kinect from one place to another, or he has the Kinect placed right in front of, or on top of, a speaker.
I wish they didn't have to rely on the calibration process so much. Unfortunately there currently isn't a better way to do it.
Am I understanding this correctly that it is quite crucial that the loudness at which you issue your commands are calibrated properly? From previous posts, I was under the impression that this tech is that good, that it would work good enough, irregardless if I am sitting in the same spot where I calibrated it or moving around the livingroom - and assuming that livingrooms vary in sizes, from small to large or having various ambient noises. It might be easy to equalize out sounds going through the Xbox, but what about different noises - noisy road outside etc.
I guess that's something you can't say, but if judging by that video the commands don't work well enough with what I figure to be reasonably calibrated in a more or less quiet room - what about less optimal circumstances (e.g. large room, more ambient noise, people moving around)?
I'm not disputing that the tech can work well indeed - but I question how often this is the case in the average livingroom outthere. How well were these things tested? Did MS test these things out in the field (e.g. employers homes) or were these tests confined to offices where these things are simulated to some degree?