These cave build houses are the best videos. I'd love to have one myself. ever since I saw the first wonder woman movie with Cathy Lee Crosby back in 1974 when the bad guy lived in a cavern with a big glass wall looking into the grand canyon.
I'd build it like an old Roman bath house with a cavity under the floor and a fire pit out front with the exhaust flowing through the floor and up a chimney at the other end of the house so the floors are heated in the winter. A simple layer of cinder blocks on their side and a concrete floor over them would be enough to carry the heat to the chimney.