There are classic elements to this movie, but it's undone by excessive padding and too much talk that makes the movie drag significantly. It might have been better as one of the hour long Twilight Zone episodes.
"Worthington, we're being attacked by giant bats!"
But the thing is that the late 50s - 60s Twilight Zone episodes were great. Imo OP is spot on that this film felt like a little longer episode from the series.
There are classic elements to this movie, but it's undone by excessive padding and too much talk that makes the movie drag significantly. It might have been better as one of the hour long Twilight Zone episodes.
Yeah, sci-fi in the golden age required it's viewers to understand "padding" and intelligent conversation. Today's video game generation movie watchers slip into comas if there isn't an explosion, car crash, sex scene, or martial arts fight every few minutes.
I think it was just about the right length of time. I don't really think it was padded because most of these 1950s sci-fi movies were pretty short by modern standards. Although it does have a twilight zone feel to it as do a lot of these movies, probably just because they were made in the same time and place.