I wanted to see it again before showing it to you : it's the craziest science fiction film I've ever seen. So I saw it again : it makes Alice in Wonderland seem reasonable. A madman's film. Produced by Gerry and Sylvia Anderson (AKA Lady Penelope) and their usual collaborators from their "supermarionation" series. They always wrote together, Sylvia drew the costumes and spaceships, the weapons of the future, the furniture, etc. Even Japan was fascinated and one of the creators of the Sony Walkman told me their vision of the future had inspired him. Doppelgänger was their only feature film with real actors but they would do it again with the TV series UFO.