Jack is a brawler, yes. But he's always used his brain as well. But now, according to this book, he's nothing but a remorseless killer, mowing down anyone who comes up against him. The author could have had fun with this, Jack could have played off the two opposing factions. against one another with intention - and no one necessarily had to die. Problem was the author turned jack in to a battering ram of death, and even his wish to help the old couple come across as psychotic rather than defending the rights of the 'little guy'
also the waitress sleeping with Jack - her reasonings? this came off as a male author's fantasy rather than what would happen in real life.