The prohibition era in the United States created an environment in which organised crime flourished and produced a number of well-known gangsters with colourful nicknames. Machine-Gun Kelly, Baby Face Nelson, Legs Diamond and Pretty Boy Floyd are some examples. They all achieved notoriety in their careers but also became a source of fascination for the public who wanted to know more about their lives and personalities. Gangster movies were particularly popular in the 1950s and during the period 1957-1960, movies about each of the aforementioned anti-heroes were released.

Roger Corman's "Machine-Gun Kelly" provides a fast-paced and exciting account of Kelly's career after he'd graduated from bootlegging to bank robbery and although not everything depicted is factual the characterisation of him as being dominated by his girlfriend and having an inordinate fear of death and everything associated with it (e.g. coffins, wreaths, a tattoo of a skull and crossbones etc.) is undoubtedly more accurate.

George "Machine-Gun" Kelly (Charles Bronson) and two other gang members carry out a bank robbery during which Kelly kills a security guard. The three men make a well-planned escape by dumping evidence as they travel and switching cars before Kelly meets his girlfriend Flo (Susan Cabot) and they successfully get through a police checkpoint before returning to their hideout close to "Harry's Gas Stop". Harry (Frank DeKova) is also a member of the gang and is desperate to be paid his share of the loot. When Kelly insists that he'll have to wait, Harry threatens to turn his caged mountain lion on him. Kelly gives in to this threat but after giving Harry the money, throws him against the cage where he immediately gets clawed by the lion.

When another gang member, Fandango (Morey Amsterdam) arrives at the hideout with the proceeds of the robbery (which had been passed to him during the car switch), Flo soon realises that he's already taken his share and this causes Kelly to lose his temper and attack Fandango. Flo then plans a second robbery and gang members Howard (Jack Lambert) and Maize (Wally Campo) who had participated in the first robbery, follow their instructions correctly but everything goes wrong when Kelly sees a coffin being delivered to a mortuary and can't function to carry out his part of the plan. Maize gets killed as he and Howard are making their getaway and shortly after, Howard leaves the gang.

Flo is the driving force behind Kelly's exploits and with her encouragement, he decides to kidnap the daughter of a wealthy businessman. This decision proves to be disastrous and eventually leads to the end of his criminal career.

Kelly's unreliability caused by his insecurities about death and his ill-judged treatment of the other gang members, led to the disintegration of his gang and provoked Fandango into betraying him. His weakness in allowing himself to be dominated by the manipulative Flo, who had openly ridiculed and taunted him, also left his destiny in the hands of someone who was utterly self-centred and driven by greed and ambition.

Charles Bronson in his first starring role capably shows the various sides of Kelly's character and Morey Amsterdam provides the best of the supporting performances. Roger Corman's legendary skill at directing on low budgets is evident throughout this movie and the way in which the first robbery is filmed stands out as being economical, effective and quite original.