CarcinoGent’s review published on Letterboxd:
The Big Combo is a stylish crime film with an appropriately twistng plot and a cast of (mostly) compelling characters. While the lead character, portrayed by Cornell Wild, can be a touch bland, we're treated to a great scenery-chewing turn from Richard Conte as the villainous Mr. Brown. A pair of (gay?) henchmen, a nightclub singer and an antique store dealer with a secret are all welcome and colorful additions
As far as negatives (other than a dull lead), the movie has a few clunky/ cheesy lines that may give some viewers pause. They do not detract much from the film as a whole, however, and are the only script-level issues I noted. The rest of the screenplay is pretty great, with the mysterious background of the antagonist serving as the primary driver for our obsessive hero.
As mentioned previously, this is a stylish flick. Its world of shadows reflects the spiritual bleakness of the story. It's also a violent movie, with sequences of physical as well as psychological torture.
All-in-all, a worthy noir.