I saw this movie in the early 1970s and it was a great matinee entertainer. Lots of action, thrills and spills. Neat sets (for the time) and a strong lead (Stuart Whitman) with good supporting characters. Remember that this is essentially a bit of low-budget escapism, don't expect too much and you'll enjoy the ride. Great, harmless way to get youngsters interested in sci-fi - and a marvellous excuse for Dad's especially to relive their growing years as they watch along!