Filmed with live actors and actresses in black and white and rotoscoped, with animation cells placed over every frame of the cast members to create animation that's more fluid and realistic than standard animation.
Even though the rotoscope performers get top billing in the opening credits, Ralph Bakshi had some of the voices of the characters dubbed based on what he wanted and the abilities of the cast. For example, Cynthia Leake performed Teegra during the live action shoot. However, after the animation was done, Teegra was voiced by Maggie Roswell.
According to director Ralph Bakshi's commentary on the DVD, the animators found working for producer Frank Frazetta to be so daunting that some of them even fainted when Frazetta visited the set.
Over a thousand background paintings were done for this film. Eight to ten paintings were done per day.
The two credited writers for this film, Roy Thomas and Gerry Conway, were well-known comic book writers, and both had served as editor-in-chief at Marvel comics in the 1970s. Thomas took over the position from Stan Lee in 1972, and Conway held it briefly in 1976.