The idea of going undercover to get a job done is not new, in American cinema it probably goes back at least to Undercover Agent (1939). Police procedurals being popular, almost every other country on the planet has played with this genre also, and it is especially popular in Asia. Masato Harada is a senior director with decades of experience in Japan and this appears to have been his pet project. References in the film show that Harada was very familiar with the American "film noir" (as above), and in many ways Hell Dogs is almost an homage. That said, while direction and acting is sharp, and the action scenes razor-sharp, my concerns are the same ones mentioned in the overseas reviews. Running over 2 hours is just too long; long scenes of exposition with heavy dialog; long distances between action scenes; and so many characters to keep track of that the viewer gets the sense a pop quiz may be coming. Tighter editing would have helped. ((Designated "IMDb Top Reviewer." Please check out my list "167+ Nearly-Perfect Movies (with the occasional Anime or TV miniseries) you can/should see again and again (1932 to the present))