There are stories that can be contained in an one-shot, and there are stories that cannot. Trying to cram the latter kind into a one-shot is a mistake made very often.
The story introduces us to the characters, gets us curious about them and immersed in their lives... and then it ends. The manga visibly tries to convey a message, but it doesn't manage to. The climax – those few slides just before the ending of a one-shot, where the moral of the story is unveiled – is too vague. It's very obvious that there's a full-scale story in the author's head, but we only got
to see a teaser. The rest will likely never be known to the world, and that's unfortunate. The characters have a pull to them; they are well-drawn and well-written, and I wanted to know just a little more about them, but was harshly denied the pleasure.
White is one of those stories that are not suited to be one-shots. It's great while you read it, but the final impression is that of frustration.