This amounts to Fritz Langs' "Metropolis" (1927), mixed with a good dose of "sword and sandals" film, with plenty of cheesecake and beefcake.
In Atlantis Obro is on a quest to Metropolis, to warn its king Yotar that his misuse of science will cause the downfall of Metropolis and all its residents. Suddenly, Obro and companions are hit with a "magnetic death ray" that only Obro survives, the others being turned into skeletons. Obro is then taken by soldiers to the King, who has him selected for a brain transplant for his son, because Obro is of "superior blood". The whole film plays like a Flash Gordon serial.
Gordon Mitchell is a suitable hunk of beefcake, who throws soldiers and boulders around like they were toys. Rodalno Lupi bears a resemblance to Charles Middleton, who played Ming the Merciless in at least one Flash Gordon serial. Bella Cortez's Mesede resembles Princess Aura; here she is redeemed by her love for Obro.
The futuristic Art Direction is by Giorgio Giovannini, who worked with Mario Bava on 1965's "Planet of the Vampires", and other Bava films. The sets and set decoration borrow from the Mayans, Aztecs, Egyptians, and Chinese, depending on the scene.
The cinematography is by Mario Sensi. The wild color scheme resembles that of "Planet of the Vampires" (1965) and "Hercules in the Haunted World" (1961), except the dominant color is red instead of orange.
The script is wonderfully stupid. My favorite line; Obro to Mesede : "We're made alike!" Not really, although they both have big chests.
Watch for the wedding dance, and the swords that look like canoe paddles. Last half hour of the film must have used a ton of dry ice. In spite of being great fun, I can only give it a 4/10.