These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Moral Event Horizon: The hunter crosses it when he kills Vuk's entire family early in the movie.
Nightmare Fuel: Many characters (even developed ones who had several lines) get not only killed, they are also eaten by our main protagonists. One scene has the title character devouring a duck 'till only its head remains. At no point are they drawn realistically — everybody you see getting mauled is an honest-to-goodness cartoon character. Thankfully explicit Gorn is avoided, however.
Sequelitis: The second one, made in 2008, is pretty much the complete opposite of the original.
So Cool It's Awesome: The original is not only considered a great animated film; it is considered one of the best ever made.
What Do You Mean, It's for Kids?: The movie is definitely a children's cartoon thanks to disneyfication but the novel (by extension most of István Fekete's works) is also considered children's literature in Hungary. Yes. Despite the violence, death, moral ambiguity, heavy themes and general lack of sugarcoating.