Sonic Unleashed is a platform game in which the player controls the titular Sonic the Hedgehog in two modes: fast-paced levels that take place during daytime, showcasing and using Sonic's trademark speed as seen in previous games in the series, and slower, night-time levels, during which Sonic transforms into the Werehog, and gameplay switches to an action-based, brawler style of play, in which Sonic battles Gaia enemies (those created by the main enemy in the game, Dark Gaia).[3][4] Each level takes place on a particular continent, each of which is based on a real-world location.[2] In sections of the PlayStation 3 and Xbox 360 versions of the game, the player may choose to advance the time of day in order to play as either Sonic or the Werehog; in the PlayStation 2 and Wii versions, time is advanced automatically.[5]