The game's development began in 2006 and lasted 18 months, after the creation of its game engine, the Hedgehog Engine. 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. 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. Gameplay features two distinct styles, with each being played either during daytime or nighttime.
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 having become a 'Werehog', a werewolf-like transformation, which he gains after coming into contact with the energy of Dark Gaia. Sonic Unleashed is a 2008 platform video game in the Sonic the Hedgehog series. Platformer, action-adventure, beat 'em up
