You admit that; examining a species (genre) and / or sub-genus (sub-genre) is an issue in itself. The first problem emerges at the point of choosing which film to include or not. For example, in March 2011 on IMDB, the most comprehensive movie source on the internet, had 1914 long-film films labeled “crime” keywords. (As of May 2011 I look forward to 1937, 2190 as of January 2012!). In other words, the most comprehensive internet database suggests that there are more than 2000 feature films that can be associated with "crime". Be sure that there are more movies with the same qualities. Blue Velvet (1986),
Gran Torino (2008) and Legends of the Fall (1994) also feature films from countries such as Korea, Spain and Japan in the selection of IMDb as well as films from countries. As a matter of fact, there is a great responsibility here to those who examine the gangster movie: Which movie can be considered a gangster movie, which can not be chosen. This job is not as easy as it looks at first sight. It may be easy to push the films of Slumdog Millionaire (2008), Golden Ninja Warrior (1986) or Belle de Jour (1967) out of the total (which IMDb labeled these films as gangsters), but Kill Bill Volume, The Dark Knight (2008) or Mystic River (2003)?