My version of the ending
Maybe the director just made such controversial ending on purpose to make it look "cool" and make the viewers wonder and interpretate how it all was? ;)
Everybody want to be it a happy ending as Kenji finally goes to meet Noi to Osaka (well, he wasn't responsible for those deaths, only for the fact that he didn't call the police after his bro was shot and left two bodies inside his apartment, this wouldn't be hard for the police to reveal everything). So finally he goes there and meets Noi, all are happy and satisfied.
However the "sad" ending is thought to be more possible by many viewers since a good film cannot have a happy ending, can it (well most good films ain't got no happy endings, of course with some exceptions)? So the bad ending is that Kenji is accused for all kinds of bad things he did (or didn't do) and gets imprisoned for life and then starts to dream about how he's coming to Osaka to see his only love. His earlier dreamings about the suicide and not being able to find his point of life are changed by the dreams of being together with his loved girl Noi and it becomes his point of life.
However we can look further and forsee that even despite he's imprisoned for life, Noi still can come back and see him anyway(she loved him as well, didn't she?). So you see, there's plenty of space for interpretation. I wouldn't mind seeing a sequel but of course I'm realistic and most likely we'll never know what happened next to Kenji and Noi.
That was a great film, I dare to call it a masterpiece 10/10.