First Superman Movie is Dull, But Introduces Good Small Screen Cast

Prior to 1951 Superman had appeared on the silver screen many times - in the form of short 10-15 minute serials that appeared before feature films in Superman and Atom Man vs. Superman, but Superman and the Mole Men was the first feature film (a short feature at an hour run time, but a feature nonetheless) version of Superman.
This time there's no Perry White or Jimmy Olsen - Lois Lane is the only member of the supporting cast present. The story involves Clark Kent and Lois Lane covering a story about the world's deepest oil well in a small Western town called Silsby. By the time the two reporters arrive the well has been shut down for undisclosed reasons. Kent learns that the well encountered a radium deposit before breaking through to a hollow space. Soon thereafter, some small humanoids emerge to investigate the surface world. The townsfolk react in shock and horror, and immediately form a mob - it's up to Superman to keep the peace.
The film introduces a more pacifistic Superman than we've seen in the preceding serials. The film is similar in some ways to the film The Day the Earth Stood Still, which came out the same year.
The science is actually pretty good for the period, and not having the 'Mole Men' (they are never referred to as such in the film) speak English, or any other verbal language, was a nice touch to avoid what could otherwise have been extraordinarily corny. Even so, it's not without some unintentional goofiness.
Despite having vastly improved special effects over the previous big screen Superman tales, it's rather a dull affair with Superman mostly trying to convince yokels to live-and-let-live. It does however introduce George Reeves as Superman, and Phyllis Coates as Lois Lane, who would go on to play those roles to perfection in the 'Adventures of Superman' television series. In fact, this film would later be broken up into a two-part finale of that series' first season.