was quite close to their initial design ideas. Another cited influence was the early 2D Metal Gear games. The game was a technical challenge due to the PlayStation's hardware limitations, as they needed to balance draw distance, a stable frame rate, and the gameplay requirement of seeing enemies. The nighttime setting was chosen as a suitable compromise, and enemies had to be carefully placed as clusters of them would cause the frame rate to drop. The Ki meter was included to play into the traditions surrounding ninja while giving players an alert system in the dark environments without resorting to a minimap. While Acquire could not match the budget and scope of Metal Gear Solid, which was in development at the time, they used it to spur themselves to making the game's setting and 3D environments as convincing as possible. The main motion capture actors were Sho Kosugi (Rikimaru), Naoko Kamio (Ayame), and Kane Kosugi (Onikage). Other in-game characters were performed by Tsutomu Kitagawa, Shigehiro Takeda and Yoshinari Hirose. Kitagawa supervised the motion capture process. Music The music was composed by Noriyuki Asakura, who would gain notoriety through his work on the Rurouni Kenshin anime adaptation and had worked with the PlayStation hardware on the soundtrack of Crime Crackers. He acted as both composer and arranger, and he used a combination of live and synthezised instruments. Asakura was contacted by Yamamoto during a long hunt for a composer, and Asakura was brought on board the project after sending in the opening theme "Addua", originally written for another project. Rather than limiting himself to the game's historical period, Asakura blended Japanese musical styles with Chinese, Thai and Turkish elements to create a new type of Asian music. The goal was to take this musical style and fuse it with Western rock and fusion to defy player expectations about the music. The lyrics for "Addua" are Hausa, which was used as it sounded romantic and mysterious. Asakura originally intended to use English lyrics, then standard Japanese, but both were rejected as lacking compared to the game's atmosphere. The lyrics were written by Asakura's wife Sumie, who originally suggested using Hausa. Researching the language was challenging as Sumie Asakura only had access to language dictionaries rather than native speakers. Asakura provided the male vocals for the opening theme. The female vocals were performed by Yui Murase. An official soundtrack album was released on