I Was Not Scared of This, but It Was a Wonderful Film

I was the kind of person who wasn't scared of this. I absolutely loved it. Recently watching it, the part where the parents are in the mirror and they write out help, that for some reason stuck with me. The sound design in that scene, where they're rubbing on the window, the foley they use is really scratchy and eerie. It's quite a lot for a kids' film, and I can see that kids are scared of it. And also the animation style, it wasn't like anything I'd seen before. It didn't really flow, and that just added to the whole atmosphere of the film itself.