If you go as a tourist it must be a guided/accompanied tour (or rather, you arrange it through one of DPRK tourism bodies, and they only do guided/accompanied - you can't just turn up at Pyongyang airport and ask to come in), but there is nothing stopping you having a group size of one (i.e. just yourself).
People working there and diplomats and so forth come under different rules.
Well, it wasn't me, but that's what I got from the "which is controlled by NK" comment. In short, I think he wanted to know if you could just go wander around without having government minders watching you all the time.
People working there and diplomats and so forth come under different rules.