North Korea is a defacto absolute monarchy with a 3 generation dynasty of kims. We still call it communist or a dictatorship to not give it legitimacy. The people, except the "nobles" are probably starving and serfs. Not sure how the saudis treat their people but if the same, take away their legitimacy too and call them a dictatorship.
They are not operating a communist state; they are operating a horrifying totalitarian state. In a communist state, we should see a Lorenz curve that is close to the line of perfect equality. North Korea's Lorenz curve, in contrast, can probably be used as a set square if needed. They are not communist, just dictators.
Was the Soviet Union communist? In a sense, it took the idea of communism and changed it to their liking. Is North Korea communist? Absolutely not. North Korea would be more of a simple dictatorship. The Supreme Leader claims it to be communist to give himself and his country a goal and status in the world. In truth, however, North Korea is just a simple dictatorship in which the supreme leader oppresses his people and benefits the loyal with some wealth and casts aside the rest.