An impressively-produced film. Most people seem to like it (its rating on Kinopoisk is about 7.8), though opinion is somewhat polarized and mixed. Generally speaking, many people tend to like it in proportion to how they feel about the Russian Orthodox Church. Some prefer the Soviet animated film about this battle, "The Battle of Nepryavda" (not on the site yet). There is quite a lot of discussion about its merits and of how historical it is on RuTracker. As for myself, I think that even if parts of the story are not true, it's still educational because it shows what the official state church and those who believe in its mission believe to be true and important. You can tell that many people thought this story was worth telling, and worth telling in this specific format, both by the official support from the Moscow Patriarchate and by just the sheer amount of human time that was visibly spent on it. The art style is like little else in contemporary Russian animation (except for Podivilov's other animated films), but it didn't come from nowhere - it reminds me of the art inside and on the covers of Russian Orthodox Church pamphlets that are handed out on visits to their services. It lacks anatomical exaggeration, has many lines and shading, and so is not very well-suited to animation; but they made these images move despite all that, which took a lot of work - see how long and dense the credits are...
It's also unusual in that it doesn't flinch away from the portrayal of violence, and has some real emotional impact...
I was a bit confused about aspects of the story, though this may become clear if I watch it again. I thought that the story of the two boys who decide to sneak off to join the adult men in their battle was handled quite well.
Some odd things I noticed are a frequent "stodginess" in how characters move, even in battle scenes. Also, many of the voice actors sound like religious men, not necessarily men of action (as the warriors depicted in the film might be).
The translation was pretty difficult, as the Russian language used in the film is pretty archaic and has many turns of phrase that are currently uncommon. They also usually don't map neatly onto English (at least, not without sounding very awkward and unnatural), so any translation will be to some degree a paraphrase. The original translation by Eus made in 2019 had very many mistakes and misunderstandings. A Greek Orthodox account named "pankrestos" uploaded a much better hardsubbed translation to YouTube in Nov 2023, though some mistranslations remained. I tried my best to improve on it further. There's one place at 13:14 where the words could not be made out. Some aspects of the translation are a matter of opinion. For example, the last word of the English translations of John 15:13 is usually "friends" but pankrestos had translated it "fellow man". The title of Sergey (Sergius) at the monastery is sometimes translated "Elder" and sometimes "Father". The translation of Knyaz (who leads to Russian uprising against the Mongols here) is sometimes "Grand Prince" and sometimes "Grand Duke" in English (the latter was chosen here).