Sonic Unleashed

While pursuing his nemesis Doctor Eggman across a fleet of spaceships, Sonic the Hedgehog transforms into Super Sonic and corners the doctor aboard a space station. The trap is sprung: a powerful new weapon called the Chaos Energy Cannon strips Sonic of his transformation, drains the Chaos Emeralds of their power, and fires an enormous laser into the planet below. The blast awakens an ancient evil known as Dark Gaia from the world's core, shattering its surface into seven pieces, and afflicts Sonic with a strange curse that turns him into a powerful "Werehog" by night. Cast down to the fractured planet, Sonic meets a friendly amnesiac creature he names Chip, and together they set out across the world's continents to restore the Emeralds and heal the broken planet.

Sonic the Hedgehog struggles to undo the damage done to the world and himself after Dr. Eggman unleashes an ancient evil which causes him to transform into a vicious Werehog by night.

The version of Sonic Unleashed developed by Dimps for the Wii and PlayStation 2 differs somewhat in design and and mechanics from the one made by Sonic Team for other platforms, including a different engine and fewer high-speed daytime levels.