Saw this tonight. After the first 15 minutes everyone in the audience were like:
In other words, it was rocking everyone's socks off.
It does slow down after that, and frankly you could lose 20 minutes from the middle part. Towards the end it picks up again and comes close to greatness until the crappy gun and blood CGI kinda takes you out of it.
But it's not a bad movie. I think I'd watch the whole thing again just for the first 15 min. That's the Ishii who gave us Crazy Thunder Road and Shuffle there.
Needless to say Shota Sometani is fine in the movie. He's now what Tadanobu Asano was 12 years ago. Erina Mizuno is good, too, and pretty. And the bazooka sound and the music by Blood Thirsty Butchers rocks.