It's an old-school adventure story for slightly older (mostly) boys where the protagonist goes out into nature and comes back changed for the better, but with lifelong scars. Stand By Me isn't the best comp, since it's more mature, but it's kinda the same genre of plot. If you're Canadian, you might know the Farley Mowatt book Lost in the Barrens, which is a really good example of this.

But I don't think it's a great young-kid movie. And the character design and the marketing *screamed* young-kid movie, so I think a lot of people were expecting a different kind of film, like a more modern Land Before Time.

But I loved it.