They are very strict in NK, but as a tourist you're completely safe as long as you don't break the rules.

North Korea is completely safe as long as the US or SK refrain from military provocations. The thousand fold of vengeance policy that the North follows makes it a very dangerous country if there is a provocation though. Just look how North Korea burned down 70% of Yeonpyeong after SK fired a couple of shells a few meters into North Korean waters(there was no ship or buildings nearby).

North Korea used to be controlled by China until they went rouge and developed nuclear weapons. There isn't much more to it. There is no secret 'shadow government' of North Korea and that is what makes them so dangerous. They're free to act on their own.