As usual, ignore the synopsis written by somebody who isn't terribly sure what the film is about. This almost entirely fictional gangster B-movie (the only details directly taken from real life are the main character's name and the fact that he has a machine gun) is typical of Roger Corman's cheap and cheerful output at the height of his career. Two things make it stand out, one being the performance of Charles Bronson. Long before the A-list stardom he'd eventually achieve, Bronson tended to be cast as a heavy. Here, he's a heavy with a difference: he's a coward who tries to cover it up by pretending to be superstitiously afraid of very specific things but fearless under normal circumstance, when in fact he's an insecure bully who can only act like a big man if he has a massive advantage, such as being the only person in the room with a machine gun.
The movie's other strength is that although all the major characters, and most of the minor ones, are horrible people, nearly all of them are given interestingly strange personalities, and allowed to develop in sometimes unexpected ways. I suspect this was partly accidental. The film goes out of its way to make the point that, underneath all his bragging and bluster, Kelly is the least brave and most unpleasant person in the entire cast, therefore everybody else, however basically evil they are, has to have moments where they're oddly nice or even heroic. But whether it was deliberate or not, it works. And Bronson's performance is, given the limited material he has to work with, very good. There's one scene in particular, where he suddenly drops completely out of character and becomes the weak, terrified and rather stupid little boy he really is, that proves Bronson could act when he was given the chance, though all too often he wasn't.
Although it's rather light on gangster bank-robbing action, because that costs a lot more than having people argue in a room, and Corman was always having to squeeze tiny budgets until the pips squeaked, the lengthy scenes of these lowlifes simply going about their disreputable lives and trying, with varying degrees of success, to get along with one another hold the viewer's attention in a way repetitive small-scale shoot-outs probably wouldn't. Although nowadays Corman is celebrated for his trashy sci-fi, horror, biker and drug movies, this quirky little film is considerably superior to the worst of his better-known work , and deserves to be recognized as a minor but not at all bad entry in that weirdly specific but surprisingly large genre of films about tough gangsters who are secretly desperately insecure.