Its pretty unique for a cartoon comedy show.
Its put so much work into worldbuilding, continuity, references and self-references, and the meta storyline around the show that it becomes layered in a way few comedies are. It becomes worth rewatching just to see what's going on in the background etc.
Also the action right in front of the camera isnt afraid to call out sci-fi and fantasy tropes, so it becomes a parody of sci-fi while still providing unique sci-fi stories. Thats clever as well.