Saw this a long time ago. I'm sure it was back in the early '70s on a TV station that ran Thursday afternoon Sci-Fi movies. I do recall thinking the Metaluna monster with the claw hands and brain-on-the-outside head was really cool (it still is). That mutant seemed really threatening at the time and I was surprised after watching it now how briefly it appears. As a kid, the effects were neat. Seeing it now they are obviously dated, but outside of 1953's "War of the Worlds", they have to be as good as anything else released in the middle of the '50s.

The Metalunans swipe a couple of our scientists, looking for help gathering uranium or plutonium from Earth to power their planet's defense shield. It's needed to fend off the attacks of the enemy Zahgons. Actually, a nice-guy Metalunan named Exeter does the recruiting of the scientists. He flies them back to Metaluna, but when they arrive they find the planet under heavy attack by the Zahgons. Exeter and the scientists run across some matte paintings to reach Metaluna's leader, who basically tells the scientists that humans suck and tells Exeter he's an idiot.

Exeter leads the scientist across the same matte paintings back to the spaceship as Metaluna comes under even heavier attack. I really like the look and sound of the "bombs" that the Zahgon's were dropping. I do vividly remember thinking them to be quite ominous as a youngster. They run into a Metaluna mutant for about 30 seconds and bonk it over its exposed brain with a pipe or something. They leave it for dead and take off, only to have the mutant crawl into the ship as they launch, a la the queen Xenomorph in "Aliens". It attacks them later, but dies from the internal pressure of the ship or some such nonsense.

I'll stop there. I don't want to spoil the ending, which is pretty much what you think it will be. There's a lot of grand, high-minded statements made in the last moments. The 1950's seemed to be a time when we thought pretty highly of our technology, how we might use it to destroy ourselves. Compare that to today's technology and how we use it to tell everyone what we had for breakfast or post selfies. Please, help us, Exeter.