Funny "documentary". Remember, it is 1975 year and everything in this short anime smells like 70's. Animation is quite good, reminds me American comics animation of that time. It is old school, so do not expect much. In this short anime you can find all the stereotypes about UFO: like brain washing and funny alien faces and so on. Everything in this documentary is shown like serious and scary (Oh, 70's xD ), so nowadays it can be considered even more funny and silly. Still it clearly shows the attitude of 70's people to UFO - to them it was scary and unknown. Ifyou are interested in aliens race, history and invasions or "real" knowledge about aliens - do not waste your time. This anime is about PEOPLE attitude toward aliens in 70's. It is old school. Take it or leave it.
If you decided to watch it - enjoy. This 15min will be entertaining and full of funny stereotypes, nice art and strange sounds. No real character development but you will know better how people of that time imagined UFO.