Gary Gerani, co-writer of “Pumpkinhead” (1988), ranks the film 81st in his book “Top 100 Sci-Fi Movies”, praising Doppelgänger as a “fine example of speculative fantasy in the late ’60s”. He expresses satisfaction with Thinnes’ and Wymark’s performances, the characterization (and the themes entailed, including adultery, infertility and corruption) and the “Fourth of July-style” special effects, calling the film “enigmatic”.
I thought the concept of this film was brilliant, because it would actually be possible. At least some of it. And then the “twist”… while not possible, still a pretty great idea. The film could have veered into horror at that point, but remained firmly in science fiction, in some ways even working as a companion piece to “2001”…