I see that at ending of this video, when the player gets killed by Jabberwocky, he gets then ending credits, as shown in the video below. But when it happened to me, I got instead returned to main menu without any credits. Maybe it dragged him to the ending fence where his dog ran? Also one time I had happened something similar - I let Jabberwocky catch me by running into it to check his behavior, but I got half of the "break free" meter already filled red. And when I freed myself, game ended with credits after while, but I didn´t escape with my dog yet, nor I was killed by it. But it was in final chase when dog ran to that escape fence.

EDIT: I have found the cause of the bug. After encountering the dog at the mill, when it runs to the exit fence, the game ends regardless if the player gets there too or not. Which is shame, as the main protagonist of the story now seems to be the dog instead of the boy, who we play as and the goal is to get dog to safely, either by making Jabberwock eat the protagonist or by chasing the dog out. Poor boy :-( .