Sonic Unleashed is a 2008 platform video game published by Sega. An installment in the Sonic the Hedgehog series, the story follows Sonic as he attempts to restore the world after his nemesis Doctor Eggman shatters it with a powerful laser to unleash Dark Gaia, an ancient evil, while dealing with his "Werehog" form, which he gains after coming into contact with the energy of Dark Gaia. Gameplay features two distinct styles, with each being played either during daytime or nighttime. Daytime stages incorporate Sonic's traditional platforming and trademark speed, with a combination of behind-the- back third- person viewpoints and 2D side-scroller platforming; gameplay seamlessly transitions between these two views. Night - time levels see Sonic transform into the Werehog; gameplay slows down to accommodate greater platform play, and involves combat against waves of enemies using the Werehog's brute strength.
Sonic Unleashed began development in 2006 after the creation of its game engine, the Hedgehog Engine. The game was initially conceived as the sequel to Sonic Adventure 2, but the development team began to introduce enough new innovations that separated it from previous games, and it was renamed Unleashed. The Werehog gameplay was conceived to help introduce newer gamers unfamiliar with the Sonic franchise to the series. The game's existence was first brought to light when Sega trademarked the Unleashed name, and shortly after, images and a gameplay video were leaked in March 2008. Three versions of the game were developed: one by Sonic Team for the Xbox 360 and PlayStation 3, one by Sonic Team and Dimps for the Wii and PlayStation 2, and one by Gameloft for mobile phones.
