The Left Handed Gun was adapted by Gore Vidal from his own TV play, The Death of Billy the Kid. 33-year-old Paul Newman stars as 21-year-old William Bonney, the hotheaded gunslinger known as Billy the Kid. Avoiding the usual Hollywood glamourization of this controversial character, Newman portays Bonney pretty much as he was: an illiterate, homicidal cretin. Treated with kindness for the first time in his life by rancher Tunstall (Colin Keith-Johnston), Bonney becomes devoted to the rancher; in fact, it is virtually a love affair. Soon after, however, Tunstall is killed, prompting Bonney to go on a murderous spree. In the end, Bonney must face down the other important father-figure in his life, Pat Garrett (John Dehner). In case anyone should miss the Freudian subtext in The Left Handed Gun, the closeups of Bonney fondling his six-shooter will make things crystal clear.
~ Hal Erickson, All Movie Guide