So King can do partial transformations. First time we have seen that. I'm not counting Marco because he has a mystical DF. That perfectly matches Kings fighting style. Any attack can become a deadly or stronger attack in an instant.
King tried to throw Zoro off the Island to beat him. Second time we have seen him try to beat Zoro without beating his swordsmamship strength/skill/power. It just shows King really is willing to do anything to win. He doesn't care.
The best thing about it is how Zoro is handling it. He is quickly reacting and adapting to deal the the attack or situation. That further proves how strong and skilled Zoro truly is.
Nobody should be surprised. He quickly reacted to hakai and used his skills and strength to create a large and powerful barrier haki to protect and save the other SN. Kaido and Big Mom combo attack failed to beat Zoro. They were helping each other and still failed.
Can't wait to read the chapter.