Publicity for the film announced that Bakshi had created "the first movie painting" by utilizing "an entirely new technique in filmmaking". Much of the film used live-action footage which was then rotoscoped to produce an animated look. This saved production costs and gave the animated characters a more realistic look. In animation historian Jerry Beck's The Animated Movie Guide, reviewer Marea Boylan writes that "up to that point, animated films had not depicted extensive battle scenes with hundreds of characters. By using the rotoscope, Bakshi could trace highly complex scenes from live-action footage and transform them into animation, thereby taking advantage of the complexity live-action film could capture without incurring the exorbitant costs of producing a live-action film." Bakshi rejected the Disney approach which he thought "cartoony", arguing that his approach, while not traditional for rotoscoping, created a feeling of realism involving up to a thousand characters in a scene.
