The idea that Forbidden Planet was loosely based on The Tempest is a real stretch, no matter what they say.
Compare it with Sir John Gielgud’s “Prospero’s Books”, which turned The Tempest into a beautiful work of art, the screen filled with actors playing invisible spirits, doing their enigmatic spirit things, that only Prospero could see. Each scene was like a magnificent, and dynamic, oil painting of a festival of people.
Having read a synopsis of The Tempest, I agree.