Considering it was shot in 11 days; considering its "special effects" are something less than primitive, George Reeves and this film still pack a Kryptonite-sized wallop.
Mysterious Mole-Men emerge from "the world's deepest oil well," and scare the inhabitants of the nearby town of Silsby. Despite pleas for tolerance and patience, Superman must disarm the town and protect the aliens while hard-headed Luke Benson repeatedly tries to kill them.
FACTOID #1: Despite other accounts, this film was NOT a "pilot" for the eventual series. In fact, there WAS no pilot. The day after shooting wrapped, the company spent another 12 weeks shooting 24 half-hour episodes. The comic book company decided to include a feature film as part of the schedule, so they'd be sure to recoup their investment at the box office in case no one bought the series. Lucky for us, that didn't come to pass.
FACTOID #2: Although the two-part TV version, "Unknown People," had been edited and packaged with the other 24 half-hours, it had to be withheld during the series' original run. It had been produced in 1951, and SAG rules forbade films copyrighted after 9/48 to air on TV without residuals. Not until 1960, when the rules were revised, did "Unknown People" appear.