There was also a 1954 adaptation.

The plot points are almost the same, but here they are condensed into a shorter (more child-friendly) running time. The 1950s version used rotoscoping and had a dry sense of humour, while in this version a lot of attention is paid to the art direction and scene composition, and they are quite wonderful and memorable (it reminds me of the Hungarian animated feature "Son of the White Mare", or even of Valeriy Ugarov's Music Box with a Secret).

Koschei is much more of a presence in the 1950s version, while here he doesn't even appear. Actually, the art design for his kingdom at the end of the film seems rather rushed.

The music is excellent in both, though I might prefer this one.

Overall, both are quite good, and reflective of the best tendencies in the Soviet animation industry of their respective eras.