Only you know, this movie doesn't really have an ending. First two parts were rather enjoyable, but it lacks any kind of closure. Normally, I wouldn't have anything against it - but if we're to treat it as a movie, then I'm going to demand some things. I don't need a happy ending, I don't even need an ending itself - I just want to feel the time I spent watching this movie was worthwhile.
After the movie ends, what exactly did we gain? We have the characters, we see their struggle, and we gain absolutely nothing from it. No deeper insight, nothing.
And if you say someone's too young to understand it - I feel exactly the opposite. If you experienced it all by yourself, then there's even less the movie has to offer. If you were young and sheltered then you'd be the only person that this movie would have something to offer for.
Now, it's not a bad movie per se - as I wrote before it's really pretty, the directing is nice, and it's okay for some entertainment. But there's hundreds of people claiming it's just about the best anime movie ever - and with that I came expecting a piece that's deep, that I can actually gain something from, that has some insight to offer. But there's none of that.
Ya see, that's the funny thing about this movie - it really highlights the whole 'love it or hate it' thing nicely. I don't think I've ever seen anyone think it was just 'alright'; it's either 'absolutely amazing' or 'boring waste of time'. You can count me among the former 
I guess in the end I do actually think it's just alright
