I've only seen the story of everything episode, myself, which I thought was actually amazing. Very informative and interesting and genius without being too complicated (for those without a science background). I thought it was eye-opening. I got this dvd for my dad and they started out with the aliens episode which, according to them, wasn't so great. Their complaint was that the dvd seemed to make up alien creatures and it was founded on nothing. They thought that anybody could make up whatever they wanted about aliens. This won't deter me from watching that episode in the future. Of course the aliens in the dvd were founded on nothing since there's no available evidence to go on.