Ah, bullet trap...my error, pardon my rant!
As for the rest, every weapon requires practice to maintain proficiency, especially at longer distances. Thats why we have annual quals for our soldiers, and also why very few of them shoot from longer distances; because not everyone is accurate.
Ref the 90 degrees and penetration, this is basic ballistics and penetration theory - unless an object travels at a sufficiently high speed, and has a sufficiently strong or sharp penetration ability, it will not penetrate a hard object, but will instead glance off. Try throwing a lawn dart at an object and the same principal applies. And if the device doesnt penetrate, instead landing on the ground, the whole purpose of the device is nullified, not to mention that the resulting ineffective explosion will let all the bad guys on the other side know someone is knocking. I would be much more impressed if the tape showed the weaponin actual use, not on a firing range.
Part of my disbelief is that this weapon technology has been around for over thirty years. If it is so effective, why is it used so rarely?