This movie started with promise and held interest until the last 20 minutes or so. At that point very strange things started happening with no rational explanation or relation to the plot (such as people suddenly falling through the air for no reason... and without dying, as a start). There was such an extreme amount in this movie that is totally left unexplained:
Why the mother left in the first place.
What are Oni? (The girl and her village definitely doesn't fit traditional explanation.)
What are the Snow Gods and why are they attacking Oni?
I would go on with several more items but that would get into spoilers... if it's possible to spoil a movie with no actual plot.
There are so very many strings left dangling at the end of this movie, and it is so disappointing after a promising start. I don't really understand why anyone would like this movie, nor why anyone would think it has exceptional animation, because the animation is merely average.
I would have to call the concept uninspired, the story-line unfulfilling and lazy, and the overall movie a waste of viewer time. I will never understand how scripts like this ever make it to production. Evidently the writers/director had something they saw in their mind and just took it for granted the audience would "get it". But there's not enough substance to this movie to even call it a story. It's pointless and without satisfying explanation of mysteries presented throughout-- with the audience left hanging at the end.