I've seen that video a number of times, and it makes me sad in a way. Those kids are merely rote puppets. They are not playing for fun, they're playing because it has been drilled into them. Military precision is cool for armies and marching bands, but I don't think it's appropriate for toddlers with guitars. On the plus side, though, if North Korea is anything like the USSR of old, those kids are likely getting better food and housing than many of their peers.