Not only is this an unmanned aircraft, it is an autonomous (as opposed to remotely piloted) aircraft. This means that instead of a human controlling the landing

Not only is this an unmanned aircraft, it is an autonomous (as opposed to remotely piloted) aircraft. This means that instead of a human controlling the landing, the aircraft was instructed to land and executed the descent and landing on its own. Anyone who's been involved in carrier operations will tell you that landing a jet on the deck is non-trivial even with experience. The fact that an aircraft can do this autonomously is quite impressive.