So essentially a masonry pellet stove, with thermal mass to hold and distribute the heat after the fire.
Not sure the fire would be as efficient as a
rocket mass heater, but very good anyway.
He does understand the principle of making the fire as hot as possible until combustion is complete, and only then harvesting the heat. His stove is a gasifier, and works best with
wood chips or pellets or other uniform organic material. Some of the other types of stoves he shows do work on plain sticks or logs.