Last night I watched two 50s sci-fi movies, unusual in that neither was an allegory of the invasion of Communism as so many were at that time.
This Island Earth (1955) starred Rex Reason and Faith Domergue (yeah, I know) as two scientists hired by a mysterious chap who turns out to be an alien. He wants the Earthlings to develop a power source to assist the aliens in their war with a neighbouring planet.
For its time it has some good special effects (and some awful ones) and the rubber suited mutant is just laughable. Still, it was an enjoyable hour and a half.
Forbidden Planet (1956) is literally on another planet in terms of acting, special effects and budget, Leslie Nielsen in his first acting role, Walter Pidgeon, Anne Francis and Robby the Robot star in a movie loosely based on The Tempest and which clearly had an influence on Star Trek TOS. The animated effects and "electronic tonalities" are excellent throughout. The budget for the movie was just under $2M which was unheard of for a sci-fi movie at the time.