'Nobody Knows'...for sure!

For those who have seen the Japanese movie ‘Nobody Knows’ (‘Dare mo shira nai’), I’m sure the ending must have left u scratching your head. Or was it just me?

I walked out of the cinema feeling really unfulfilled. Like the movie has just ended on me halfway through. U know there's more yet u don’t get to see it. And all your expectations are just left hanging unaddressed, which if u ask me, just isn't right.
There has to be some form of closure, even if it’s only vaguely suggested. I don’t need my movies to have feel-good endings. In fact, most of the films I like don’t explicitly present u with a conclusion but rather have u interpret for urself whether it’s this or that - ‘Before Sunset’ for example - but at least they leave u with enough to speculate the possibilities that may be.
Here, u don’t get even a nary of a hint. It just ends without any resolution, not even an afternote.

So what gives?!