Plot Holes?

What bugged me when I saw this movie are the big plot holes. Especially at the end I had the feeling that there were some parts missing. For example when the motorcycle gang angle begins there are hundreds of members. But a few minutes later when they arrive there are only a handful of riders left and one of them even falls off his bike.

So, why was the movie like this. Didn't they had enough time/money to shoot a motorcycle chase (and other stuff)? Or is the story so well-known in Japan that Miike could skip these sequences and concentrate on more importent story issues?

I mean, I kind of liked this movie. It isn't among the best movies Takashi Miike has ever done. But the story about the average man who becomes sort of a super-hero with his actions is a nice idea and it's quite rare (at least in the western world). Also I could sympathize with the characters. But there were these plot holes that made it hard to follow some time.