I saw this movie when it first appeared in theaters. I was 12 years old and a fan of the ilk. However, the methods used for special effects in that era always seemed so obvious. This movie was a novel experience: I could not imagine how the effects were done. My only reservation was that they talked of slipping through the fourth dimension AND speeding up the natural process by which an object might slowly penetrate another. These are two different ideas. The second scenario accounts for the "horror" of the movie as people are rapidly aged. It was an unforgettable film. I would like to see it now and determine whether it holds up as well as my memory of it.