The Big Heat is rather rough crime drama and pushes some boundaries for its time given its director Fritz Lang, who always seemed like he trying to find someway to bring the harder edge you'd find in his earlier crime film M. That film isn't quite as extreme as that film, yet Lang does find ways to kind of undermine the more ideal elements requested by the Hays code. Here we do have a good hero at the center, Glenn Ford in one of his better performances, but he is only into the entry point into the truly seedy underworld presented by the film. In this the film does not hold back with a vicious performance by Lee Marvin as an amoral gangster, and Gloria Grahame a gun moll who only finds a conscience after being permanently scared. The film is an effective film noir thrilling by allowing itself to fall into the darker elements needed for the genre, where Lang seems to thrive particularly in his depiction of the casual amorality of the life. Marvin's lead villain isn't this grand villain, but rather a jerk who likes to take things the easy way. Although I do think the film shirks greatness through its hero, who perhaps stays a little too clean throughout the film, but it is a memorable entry within the genre.