A western in gangster genre clothing. Or maybe a gangster pic set in a Western-era town. Either way, LMS is an ill-fitting suit, two genres maybe too close in nature to successfully mix and match.
Hill is late to the party on this one, the hired-gun going between two rival gangs. Dashiell Hammett did it better in Red Harvest. Then Kurosawa did it better in Yojimbo. Then the Coens bested them all with Miller's Crossing.
Not utterly terrible like Trespass but completely unnecessary, nonetheless.