Captain Nemo and the Underwater City thrusts several "name" actors into the specialized world of Jules Verne. Six 19th-century shipwreck victims are rescued by a modernistic submarine. The skipper is Captain Nemo (Robert Ryan), who had not died at the end of 20,000 Leagues Under the Sea as viewers had been led to believe. Instead, he has installed a fantastic underwater city, using this subterranean metropolis as a base of operations for his war against mankind. The ambitions of the screenwriters and director are defeated by the tackiness of the film's model and miniature work. Captain Nemo and the Underwater City represented MGM's first Jules Verne epic since its 1929 spectacular Mysterious Island.
~ Hal Erickson, All Movie Guide