I watched this the other day and it's pretty cool. It's animated and based on a series of manga comics. It tells the story of two young brothers living on the streets of a city.
The story involves the brothers fight against the Yukuza for control of the town. (Ironically the Yakuza want to turn part of the city into a childrens theme park to make money.)
The underlying theme of the film is the ying yang like balance between the two brothers (The films English title is Black and White - the names of the two brothers,) and what happens when that balance fails.
Change and a melancholic longing for the past (or what might have been) also seem to be recurrent themes in the various storylines.
The film uses lots of symbolism (balloons / apple trees / doves) and reminded me of a another Japanese comic book about completeness / happieness (can't remember it's name...)
I loved the magic realism and the sense of a disconnected reality that it conveyed.
I was tempted to buy the DVD, but won't as it's got a really annoying copy protection system used by Sony which meant it didn't work in my media centre :s