I might suggest a short popup screen once you get to the open exploration bit that tells players the controls. I have been wandering around mashing buttons at npcs just to see if they can do anything. So far ive only found the end of demo area, and have not been able to interact with anything/anyone otherwise.
Also you can fall off the world near the large tree on the island on the left side of the map. The one with all the busted bridges leading to it. Just walk down to the right of the bushes on the far left.
Really enjoyed the first game and looking forward to see where this one goes!