@Flinn, i dont know if a "just" fits here at all. You are not wrong tho as for which part of the source material is covered.
I know this may now seem funny, but who is to say if the future generations will not unearth this, and not "the other one" of the Tolkien's adaptations, and in the collective memory of our distant seccessors it will be this soviet version that lives on.. oh man its hard to write this sentence even if i will be long gone by that time.
As a side note, there is also a soviet Hobbit, from 1985 if i recall, and its also good...