Like a 50's version of Star Trek. It's Star Trek 0: The Forbidden Planet, anyway.
I've seen it that way. Indications that Roddenberry was thinking along those lines can be found in Cpt. Pike's hat in The Cage. He never wore it, but it was on the dresser with his holster. The look of The Cage sets was also highly suggestive of Forbidden Planet.
So we have been watching Forbidden Planet the Series all along.