AllMovie

This odd little film plays like a Mexican variant on the goofy serial Phantom Empire (which pitted singing cowboy Gene Autry against death-ray-wielding subterranean villains). Gaucho star Gaston Santos rides out to do battle with a rubbery swamp monster, avenge his father's death, and rescue the girl -- all while belting out a few snappy musical numbers. This muddled mix is rendered even more senseless by the domestic repackaging of producer Gordon Murray, who had new scenes shot featuring painfully unfunny attempts at comic relief -- which really wasn't necessary to begin with, considering the inherent lunacy of the original. Released in the U.S. as Swamp of the Lost Monsters.