This test is very similar to a test of a Titan II ICBM first stage test from the 1960’s. We see an orange cloud at initial firing that is rich in Nitrogen Tetraxoide oxidizer. We also see two smaller side plumes from the visible main engine. This leads to the conclusion that it’s a firing of an engine pair very similar to the Titan II. These side plumes come from the main engines turbopumps which are driven by small rocket engines using the same type of fuel as the main engines. From these observation we can conclude that the engines are for an ICBM of the Titan II class! This is very BAD for the world as this class of ICBM’s is capable of putting a 10,000Lb object into orbit or landing it anywhere in the world. Something like a large nuke maybe!!
I have some experience in this area as I have over 200 Alerts in Titan II silo’s!
I pulled close to 400 Alerts as a BMAT and was in the Instructor Shop for a few years. I was looking at the exact same things you mentioned here. They may be perfecting the system for a large liquid fueled ICBM but, as you know, the system is complex and prone to leakage. There were many trials and tribulations bringing the Titan II into being and they will need to overcome the same obstacles. It could be bad for us if they do.
Yes, it is very bad.
Jeffrey Lewis tweeted that it might be a https://en.wikipedia.org/wiki/KN-08 “I make the diameter of the new DPRK engine to be about the same as the engine tested for the KN-08 last spring. Some cautions.” https://twitter.com/ArmsControlWonk/status/843478057658732544