First Rate Film Noir
Although apparently shot on a tight budget, this is a first rate film noir with a fine cast, brisk pacing, effectively built suspense and First rate cast, and a "humanizing" touch that gives the characters some depth and helps the audience realize they aren't all just "villians," out for a quick score because they like money and crime.
Kubrick was a brilliant director, but it's a shame he didn't make more films like this tight, taut, thriller.