Certainly one of the best entries in Animos studio's "Russian Classics for Children" series. This film is so rich, and everything (acting, art direction, screenplay, music) seems to be in top form here. Nor does it simplify the material or seem to speak down to its audience, like some of the other films in the series. The source material is curious - a story written by a writer who left Russia because of the Revolution. Not something that could have been adapted during Soviet times, I think. Eus, who originally submitted this (and may have made the first version of the English subtitles, 13 years ago) wrote "Personally this animation made me understand the Russian obsession with/enchantment by an even more famous Russian Poet & Writer: Aleksandr Pushkin".
I will say, though, if showing this to children, it probably helps if they are familiar with the Krylov fable in question (though that is very likely to already be the case, if they are Russian).
There is no great English translation of the original Krylov fable that I've found online, by the way. Perhaps the one by Lydia Razran Stone in the book "The Frogs Who Begged For A Tsar (And 61 Other Russian Fables)" is good (because some of the others in the book sample seem nice enough), but it can't be found online.