Sonic Unleashed did have a presence at this year's E3, but only behind the closed doors of Sega's private booth, and only on the Xbox 360. The build on display had some kinks to work out, but the hands-off demonstration and discussion with the Sega representative provided some insight as to what to expect on the Wii.

Firstly, the PS3/Xbox 360 version of Sonic Unleashed (henceforth referred to as the HD version) are different from the Wii (and PS2) version, although they have much in common. Sonic Unleashed HD is being developed entirely by Sonic Team. In contrast, the Wii rendition is being developed by an unspecified third party (despite direct questioning), with level design support from Dimps and Sonic Team's oversight. Dimps was responsible for the critically acclaimed Sonic Advance series for GBA, as well as Sonic Rush on DS, so the Wii variant holds some promise. In short, although the Wii and HD versions share the same premise and overall gameplay, the game engines and level designs are distinct.

Both versions contain two primary modes of play: daytime levels and nighttime levels. During the day, Sonic is his speedy self, dashing and platforming through bright and sunny sites. Settings are largely inspired by real-world locales: the two demoed resembled Milan and The Great Wall of China. Level designs are a mixture of 2D and 3D sequences, smoothly transitioning with automatic camera control. Indeed, the revamped camera looks to be the subtlest big change in the series for the HD version displayed—how it behaves on Wii is unknown.

Nighttime levels take on a slower pace when the hero transforms into Sonic the Werehog, a brutish, cartoony monster with stretchy arms perfect for pummeling baddies. The nighttime levels have some platforming elements and his arms allow him to reach ledges, but this mode is primarily a brawler, complete with a combo meter. Sega stated that the game features roughly a 50-50 split of night and day levels.

There are other changes to the standard 3D Sonic formula. For example, rings double as a health and power meter. Collecting rings will allow Sonic to enter a heightened state, in which he'll reach even faster speeds during the day and be stronger at night. This boost of speed allowed Sonic to run on water in one section of the demo. Sonic no longer loses all of his rings when hurt: during the demo, taking damage only cost Sonic ten rings. Sonic can also perform a "swipe" move (using the trigger buttons in the 360 version), which shifts Sonic to the side without affecting his trajectory, much like changing lanes on the freeway. Although the Wii edition will incorporate gestures, players uninterested in motion controls will have the option of playing with a GameCube or Classic controller.

With 2D sections, a new camera, and tweaked game mechanics, Sonic Unleashed HD aims to set itself apart from the “me too” Sonic iterations from the last console generation. It is unclear how much of what NWR saw at E3 2008 applies to Sonic Unleashed on Wii; hopefully Sega will shed some light as development progresses.