[La Soufrière] is one of Werner Herzog's most exquisite efforts, a perfect distillation of his talents…. [The] film is a serene, strangely clear-headed documentary about the end of the world….
"Heart of Glass" [is] a feature by Mr. Herzog that is far less successful. Mr. Herzog hypnotized his entire cast to film a parable about a medieval town that has thrived by producing ruby-colored glass, until the only man who knows the formula dies….
In its own way, "Heart of Glass" is as much about the end of the world as is "La Soufrière," but ["Heart of Glass"] is much less accessible, and often obscure. The actors' trance is contagious, and the film has some genuinely mesmerizing moments, as when the town seer, whose words have made little sense, suddenly begins to predict an alarmingly familiar future in which "no man will like another man." Mr. Herzog seems not to be working with real actors, but rather with apparitions.
At times, the script reads like a collection of nonsequiturs. "Do you want our people to eat oatmeal bread again, that gives them headaches?" asks one character. "Rats will bite your earlobes," someone swears. Even the film's meticulousness—every trace of red anywhere, even on a goose's head, is clearly planned—is not entirely decipherable.
The elusiveness of "Heart of Glass" makes it something of a disappointment. But it is too mysteriously lovely to be regarded as a failure.
Janet Maslin, "One by Werner Herzog Soars, but 2nd Doesn't," in The New York Times (© 1977 by The New York Times Company; reprinted by permission), October 1, 1977, p. 10.