I just re-watched this the other day and it impressed me quite a bit. One thing is the interesting location work: yeah, the kind of Manhattan street scenes you'd expect, but the sequence where Conte breaks out of the prison hospital uses a very nice combination of sets and unusual locations. But another strength of this film are the one-off characters who show up for a scene and are never heard from again: the dim turnkey at the aforementioned prison hospital, the receptionist at the crooked lawyer's office (introduced just long enough to take a bullet), Shelly Winters (playing--very briefly--an old girlfriend of Conte's), the unlicensed doctor with the sick wife, the drunk Ms. Winters meets in the bar, the final female horror that Conte has to deal with (the way she's introduced, btw, is one of the greatest examples of deep focus in all of motion picture history). All the actors, with a few quick lines, lend a remarkable vividness to each of the characters they portray. This is not your typical noir cheapie, this is an A picture through and through. There's a reason Scorsese singled it out in his Journey Through American Films documentary--it's a great film on every level (well, except for the music).