The game, in addition to existing single-player Career modes, includes a new Co-Op Career mode and competitive challenges that pit the player against in-game characters and other players. Guitar Hero III: Legends of Rock retains the basic gameplay from previous games in the Guitar Hero series, in which the player uses a guitar-shaped controller to simulate the playing of lead, bass, and rhythm guitar parts in rock songs by playing in time to scrolling notes on-screen. Aspyr published the Microsoft Windows and Mac OS X versions of the game, releasing them later in 2007. The game was released worldwide for the PlayStation 2, PlayStation 3, Wii and Xbox 360 in October 2007, with Budcat Creations assisting Neversoft on developing the PlayStation 2 port and Vicarious Visions solely developing on the Wii port respectively. It is the first game in the series to be developed by Neversoft after Activision's acquisition of RedOctane and MTV Games' purchase of Harmonix, the previous development studio for the series. It is the third main installment in the Guitar Hero series, following Guitar Hero II. Guitar Hero III: Legends of Rock (initially referred to as Guitar Hero 3) is a music rhythm video game developed by Neversoft and published by Activision.