His first venture into directing was in year 2000, when he got to direct the opening of Party 7, a film directed by Katsuhito Ishii. Koike also acted as the character designer and animation director on the film, getting to fully display his influences from above-mentioned legendary animator Yoshinori Kanada as well as Mike Mignola, an American comic artist of Hellboy fame.
Some time after this began the notoriously lengthy seven year production of Redline. The film was eventually released in August 2009. Despite the positive critical response, with particular praise for its animation, Redline didn't have a successful run at the box office. It did however see a much greater success after its home release and has since been recognized as a cult film.
