Superman’s movie history has gone in every direction possible. He has flown high in some films and crashed hard in others. Some movies earned praise and stayed in people’s minds for decades.

This fascinating though incomplete documentary tells Paul Reubens’s story despite the subject’s doubts about the project.

He joined the L.A. comedy group the Groundlings, where one of his characters was Pee-wee Herman, a clean-cut man-child with a ...