I was a schoolboy when I watched this film for the first time. The next day I knew that all pupils of our form watched it and all were fascinated by the film as I was. I think the same situation was in all forms of our school and in the whole Soviet Union. Later I watched it every time it was shown on TV and want to watch more. I think that comparison with "Back to the Future" or other Sci-Fi films is not appropriate. "Gost'ya iz budushchego" is unique in many ways, once you have watched it, you never forget it.
This film is full of belief in peaceful science achievements, full of belief in the beautiful future of our world. It's not only the film, but also a forecast of many scientific inventions and achievements. The time shown in the film is the year 1984 (the year of its creation) and the year 2084 (where a schoolboy Kolya Gerasimov has traveled for some time and where his friend Alisa Seleznyova was from). The year now is 2005, many inventions and achievements predicted in the film are not realized yet. Such as "Mielophone" (a device, which can read thoughts of any animal and human), expeditions to Venus and Mars (as easy as going for a picnic in the weekend), creating and launching of the satellites as a homework for pupils, easy to drive flying machines (which completely replaced automobiles), biorobots, "historical identification" of any kind of material or creature performed in a couple of minutes, and many others. Meanwhile, some of them nowadays became much more realistic than they seemed in 1984! Just wait for 2084 :-)
The film also depicts typical Russian schoolboys and schoolgirls (and does it so naturally!). With their inventiveness, curiosity, humour, dreaminess. Look for example at Fima Korolyov, you could find such character in nearly all forms of every school of the Soviet Union, similar character was in my form too! Alisa Seleznyova... I myself, as well as many my classmates fell in love at first sight with her! By the way, later an actress who played Alisa became a scientist - I think she was as much influenced by the film as people who watched it on TV.
Beautiful idea, beautiful realization, beautiful actors, beautiful music, beautiful song "Prekrasnoye Daleko" ("The Wonderful Far-Away")... Beautiful, beautiful, beautiful...
The last thing I want to say is that different remakes and "new versions" of the song from the film and even the film itself were made later and spread on TV and in the Internet. All they are not even comparable with the original. I should not even comment them, my comment is only about the original. So, request the original and enjoy it!