This movie is based off of an incomplete book that the author died before finishing. Why make a movie like that in the first place? I dunno... the film seems to remain around the same amount of incomplete as the source material, so there isn't much of a plot or main conflict. (There is a set-up for what the plot was supposed to be, but once you get half-way through the movie and there isn't any word on it you realize the movie isn't going anywhere with it.)
This turns it into more of a "slice-of-life" movie. You just follow the main character after she gets adopted by a witch and watch things unfold. And that, all things considered, is fine with me. I enjoyed the movie. It has a quirky cast of characters, cool music, and something new to many of us, CG Ghibli animation. Which by the way, is quite good, so don't worry.
So, I'm disappointed that we didn't get to see the whole intended story, and I'm also disappointed that we didn't get more plotless slice-of-life time with the characters. But, it's a cute movie. Family friendly, but not too childish. If you're okay with just sitting down and watching something, I recommend it. It doesn't follow the typical "rising action, climax, resolution" movie formula and that's ok. Don't write this one off. I think the other ratings are a little harsh.
