Rocket Ship (1938) is a spin-off of the original Flash Gordon series and a movie I recently watched on Tubi. The storyline follows a planet fast approaching Earth led by Ming the Merciless. Ming looks to use his planet much like the Death Star to destroy Earth. His planet is also filled with all kinds of strange and unique aliens from other planets he's conquered. Flash Gordon is a scientist who believes he can fly into space, land on the invading planet and stop it from destroying Earth.
This movie is codirected by Ford Beebe (The Invisible Man's Revenge) and Robert F. Hill (Shadow of Chinatown) and stars Buster Crabbe (Buck Rogers), Jean Rogers (Charlie Chan in Panama), Charles Middleton (Duck Soup), Priscilla Lawson (Rose Bowl) and Frank Shannon (Blonds at Work).
The storyline for this is classic science fiction and while very straight forward it's executed well. The invading planet is so well created and contains fun landscapes and creatures, with the creatures made up of people in suits and iguanas. The acting is actually very good as are the props, costumes and sets. The monster in the cave was cool and the fight with the guy in the gorilla suit was hilarious and fun. Ming was perfect in this with a good mix of diabolical and arrogance.
Overall this is a science fiction gem that isn't perfect but is very entertaining for a 1930s picture. I would score this a 6.5/10 and strongly recommend it.