Judged on the basis of novelty, as a showcase for the Tru-Stereo Process, Robot Monster comes off surprisingly well, considering the extremely limited budget ($50,000) and schedule on which the film was shot.
The Tru-Stereo Process (3-D) utilized here is easy on the eyes, coming across clearly at all times. To the picture’s credit no 3-D gimmicks were employed.
Beating Arch Oboler’s Five  by one survivor, yarn here concerns itself with the last six people on earth – all pitted against a mechanical monster called Ro-Man, sent from another planet whose ‘people’ are disturbed by strides being made on earth in the research fields of atomic development and space travel.
Sextet – a famed scientist, his wife, assistant, daughter and two children – are protected from Ro-Man’s supersonic death ray by anti-biotic serum.
Of the principals, George Nader, as the aide who falls in love with and eventually marries the scientist’s daughter in a primitive ceremony, fares the best. Selena Royle also comes across okay, but of the others the less said the better.