planned for the sequel to take place a year after the first and originally intended for the events of that year to be left unexplained. To bridge the gap between the two games, Kingdom Hearts: Chain of Memories was developed. Nomura was hesitant about releasing a game on the Game Boy Advance because he felt the 3D graphics of the original game would not translate well into 2D. He changed his position after hearing that children wanted to play Kingdom Hearts on the handheld system. Creation and design Though Disney gave Nomura freedom in the characters and worlds used for the games, he and his staff tried to stay within the established roles of characters and boundaries of the worlds. Nomura has stated that though many of the Disney characters are not normally dark and serious, there were not many challenges making them so for the story and despite this, their personalities shine because they maintain their own characteristics. He also felt managing and keeping multiple worlds was problematic. When deciding which worlds to include in the game, the development staff tried to take into account worlds with Disney characters that would be interesting and made an effort to minimize any overlap in the overall look and feel of each world. The inclusion of specific Final Fantasy characters was based on the opinions of both fans and staff. Another criterion for inclusion was whether the staff felt the characters would fit into the storyline and in the Kingdom Hearts universe. Initially, Nomura was hesitant to use characters he did not design, because he was unfamiliar with the backstory of such characters. For Kingdom Hearts II, he changed his mind after receiving pressure from his staff. Throughout the development of the games, Nomura has often left certain events and connections between characters unexplained until the release of future games. Nomura does this because he feels that games should have room for fans to speculate and use their imagination. He has stated that with speculation, even though a game gets old, people can still be happy with it. Promotion The first Kingdom Hearts was announced at E3 in May 2001. Initial details were that it would be a collaboration between Square and Disney Interactive, and would feature worlds developed by both companies and Disney characters. New characters were designed by Nomura and include Sora, Riku, Kairi, and the Heartless. On May 14,