To make things even more difficult, the film demanded 3D digital effects and numerous crowd scenes. Maruyama, a producer and representative of Mad house, confessed later, saying requesting a digital shooting itself was an impossible order. By surpassing everyone's expectation, DR successfully completed the work and its advanced digital techniques became famous in Japan.
As for the DR animators, 'Metropolis' was difficult one because they had to draw more than 40% in-between animations.