Maybe its my advanced age, but I found this movie to be very difficult to follow. The movie starts off in the middle of the story and then tries to fill the viewer in with flashbacks. I love the character that Liam Neeson usually plays. In this movie his character is more vulnerable and therefore more human. But you have a hard time figuring out what is going on. The plot is not helped that at first the bad guys are motivated by pure evil, not really by a profit motive, but then money does become part of the story line, but it would be a spoiler to describe how. The fact that ransom money gets involved takes the movie in a new direction that weakens what was an intriguing character study. It was a little strange that the author/director hid the identity of the bad guys for a while when there was no point in doing so, and then made no effort to explain why at first we saw them only in shadow. There are continuity problems, because the Neeson character knows more than we do, tells us so, but we don't know why he does. To sum up, I think that strange things happened to this movie in the editing process.
For those who tolerate reading Deadbird loving Will Leitch, here is his review of "A Walk Among The Tombstones". Although he and I have our differences when it comes to baseball teams, we seem to see eye-to-eye about the plot of this movie.
http://theconcourse.deadspin.com/the-badass-action-hero-rebirth-of-liam-neeson-1636779213/+timgrierson