Sonic Unleashed - Development

Development

Sonic Team began development of the game in 2006, after having begun work on the core technology, the Hedgehog Engine, in 2005. The title was first brought to public attention when the Sonic Unleashed name was trademarked by Sega on March 12, 2008. Screenshots of cut scenes, artwork, and a video were leaked ten days later, with the title then officially confirmed by Sega on April 3, 2008 with a small selection of screenshots and an updated video. The game was developed internally by Sonic Team in Japan. It was originally intended to be the third installment of the Sonic Adventure series and subsequently, at an early development stage, had the working title Sonic World Adventure, complete with work-in-progress logo. However, the development team began to introduce enough new innovations to separate it from the Sonic Adventure titles, and so a new title, Sonic Unleashed, was decided upon. It was then later revealed that the game's name in Japan would in fact remain Sonic World Adventure for its release there.

Sonic Team decided early on in the development process to reduce the number of characters present in the game, as well as to make Sonic the only playable character; this decision was taken to get more quality out of fewer characters. While it felt that these ideas combined with traditional Sonic gameplay was a good beginning, it also had to consider how to introduce newer gamers unfamiliar with the Sonic franchise to the series, and so the concept of the Werehog was born, in addition to exploring its own mythology and ideas for the story. Director Yoshihisa Hashimoto felt from the outset that there would be both praise and criticism, but hoped that long-term Sonic fans would understand and empathise with the ideas and direction the team had taken.

In terms of technology, Hashimoto remarked that the visual style was born out of desire to see a global illumination solution used for the game's lighting — that is, light reflecting from one object in the scene onto others. To this extent, development on the renderer for this process began, and the final solution allowed the developers to use distributed rendering over hundreds of computers to calculate lighting for each ten- to twenty-kilometer action stage in around two or three days. Characters, enemies and objects are then lit at run-time with Sonic Team's "Light Field" technology to blend them in with the surrounding pre-calculated lighting. Because the game was being developed for two levels of hardware capability depending on the target platform, two development "silos" were set up to work on two separate builds of the game: one for the Xbox 360 and PlayStation 3 version utilizing the Hedgehog Engine, and one for the PlayStation 2 and Wii version, which instead utilizes a modified version of an existing, internal Sega engine.

As well as the unique motion-based gameplay mechanics, the Wii version of the game also supports the GameCube controller, and also the option of using the Classic Controller. The daytime levels for the Wii were altered to accommodate the motion control-based drift mechanic, while night-time levels include a mostly behind-the-back view and different platforming styles and combat mechanics. Developer Dimps, who had past involvement in the Sonic franchise, was involved in the design of the daytime areas for these versions. In addition, overall, the PlayStation 2 and Wii versions have fewer daytime levels than the Xbox 360 and PlayStation 3 counterparts.

Initially, it was stated that Unleashed was to be intended solely as a single-player experience, and would not offer any multiplayer or online modes. This was cast into doubt when references to online modes were alluded to around E3 2008, but later interviews re-iterated that Unleashed would have no online modes at all. However, downloadable content, including additional levels, would remain a possibility after the game's release. A demo version was released on the Xbox Live Marketplace on December 8, 2008 and on the US and EU PlayStation Stores on December 18 and 24, 2008, respectively. The demo does not contain any of the Werehog stages. On March 12, 2009 Sega released Sonic Unleashed's first downloadable content for the Xbox 360 and PlayStation 3, consisting of four Chun-nan daytime stages and two night stages in addition to two new missions. Since then, more downloadable levels have been added: Spagonia, Holoska, Mazuri, Apotos, Shamar, Empire city and Adabat.

Speaking after the game's release, Sonic Team member and Sonic and the Black Knight director Tetsu Katano remarked that although he did not feel the Werehog concept was a mistake, time and resources were a limiting factor in the game's production. He also remarked that the Werehog may reappear in future games, or possibly in a sequel to Sonic Unleashed, should one be made.

Game developer Gameloft announced in May 2009 that it had secured a licensing agreement with Sega Europe Ltd. to produce mobile phone versions of Sega properties, and that its first title would be a version of Sonic Unleashed for mobile phone platforms. It was released in June 2009 in Europe, Middle East, Australia and New Zealand.