The game is played using the Nintendo DS system's "book" orientation. Solving one chapter's case changes the past, which leads to a new murder. The game is told through a series of illustrations like a book. The game features random battles but is told in a mystery story format. Neon does the fighting against enemies in the game, and can become a sharpshooter, knight, and other jobs. If players solve a mystery through guessing or illogical means, their boss battles become more difficult as the boss becomes stronger and the player becomes weaker.
Plot
The story revolves around Sigma Kurogami, a high school student and "sound user" whose family guards a huge clock sealing off the demon Ōma. One day, his past is rewritten, causing chaos in his present. He then works with his friend Neon Tsukiyumi to solve an increasingly complex string of murder cases and return his life to normal. They use Sigma's abilities and the clock to go through time, and as each murder is solved, the future changes and unlocks a new history with other crimes to solve.
Characters
Characters include Sigma Kurogami, Ōma, and Neon Tsukiyumi. Sigma has the ability to cause miracles with the sound of his voice, a hereditary family trait. Neon is part of a clan of "card wielders" that have fought against the Ouma, and also possess the power to change forms through meditation.
Development
Sigma Harmonics was first revealed as one of the trademarks registered by Square Enix. The game was developed by Think Garage, which had developed two titles in the Itadaki Street series and Lord of Vermillion. Key members of the development team previously collaborated on . The game was produced by Yoshinori Kitase and directed by Hiroki Chiba, respectively the co-director and co-event planner of Chrono Trigger. Chiba was inspired by Shōwa period writers such as Seishi Yokomizo and Rampo Edogawa, and wanted to create a video game with a similar vibe. The game features character designs by Yusaku Nakaaki. Chiba admired Nakaaki's previous illustrations and recommended him to Kitase, stating "not using Nakaaki's drawings would be a horrible waste there are lots of awesome designers at Square Enix." The game was playable at the DKΣ3713 gaming event in June 2008.
Music
The game's soundtrack was composed by Masashi Hamauzu, who provided music for Final Fantasy XIII, SaGa Frontier II, Final Fantasy X, Unlimited Saga and . The original soundtrack was released in September 24, 2008 in Japan and covers 37 tracks. The theme song "Harmonia vita" was written by Aki Hata and performed by character voice of Neon Tsukiyumi, Aya Hirano. The illustration, which was painted the protagonist Sigma Kurogami, was designed by game's character designer Yusaku Nakaaki. Square Enix Music scored the album 9/10.
Reception
Sigma Harmonics debuted on the Japanese sales charts at number 8, selling 23,000 units. As of September 30, 2008, the game has sold 70,000 copies in Japan. Famitsu gave the game a score of 31 out of 40, with grades of 8,8,7,8. In 2009 Square Enix registered a trademark for "Sigma Harmonics Coda". This became the name of a port of the game to mobile phones only divided into episodic pieces for players to download.
