This story has so many twists and turns, it'll make your head spin; but if you keep steady, you'll get a fantastic tale. The idea of "pay it forward" is subtle but constant throughout. Karma and life lessons are also important ideas for both the characters and the varying subplots. The primary plot doesn't involve only the main characters though. Every named character seems to have some influence over the entire storyline.
I drew a chart to show how each character introduced was associated to another character either more or less significant. The chart has lines and arrows all over the place. :)
The OST used fits each scene well. The scene editing is slightly confusing, but is often explained later on. There are many "Ohhh, that's what that was about" moments. The acting is good. You can see which actors are more seasoned, but the younger actors hold up well also.