This is a Soviet adaptation of Jules Verne's novel "Un capitaine de quinze ans" (Dick Sand, A Captain at Fifteen). It starts fairly close to the book and gradually diverges, ending like a western in a desert chase and shootout on the ship. Both scenes are cliché and have nothing to do with the book. The Negoro character is made even more dangerous than he is in the book, that actor who plays him however gives a good performance.
I don't agree with the other reviewer, this adaptation is not more violent than an average western movie. I think the positive side of the film is that casting is done well and characters look recognizable. Some actors play well. The main drawback is that the script diverges too much away from the book, especially at the end.
Other Soviet adaptations of Jules Verne like "Captain Nemo (Vingt mille lieues sous les mers)" or "In Search of Captain Grant (In Search of the Castaways)" are much better and closer to the books than the Hollywood/Disney ones.
