North Korea threatens to blast Seoul to ashes

After the failed launch of long-range missiles, North Korea's cornered-leader, Kim Jong Un, has been blaming the Korean government and threatened by saying, "North Korea would blast everything in Seoul to ashes."
Since the age, experience, knowledge-wisely lacking leader, Kim Jong-Un has no progress to gain support of his people, he tries to use the Nuclear test, and missile test cards as an attempt to change the flow.
However, it was an epic failure.
North Korea argued that the 'rocket' launch was for space development and a satellite launch. However, from their actions, it is obvious that by no means was it a satellite launch.
Taking no responsibility for their actions, North Korea only threatens South Korea and the US blaming the failure on the scapegoats. Nothing has changed.