Kitano reputedly had problems working with Masaya Katô. Kato had his own ideas, and Kitano would get so upset that he would yell at him. In the scene where Aniki tells Shirase to put out the cigars, it is really Kitano yelling at Kato.
Ken takes the photo of the potential blackmail victim with his right hand while his left hand is on the table. In the close-up he's holding it with both hands, and then he returns the picture with his right hand while his left hand is on the table again.
When the driver of the car carrying Aniki is shot from behind, we see his blood splattered on the windscreen. There's also a crack on it, but when we cut to the car crashing from the outside, the windscreen is clean.