StarCraft II is a sequel to the real-time strategy game StarCraft, announced on May 19, 2007, at the Blizzard Worldwide Invitational in Seoul, South Korea. StarCraft II is being developed for concurrent release on Windows XP, Windows Vista and Mac OS X. Though currently no release date has been given, it has been stated that development on the game began shortly after Warcraft III: The Frozen Throne back in 2003 and that the game development is “very far along and already playable in multiplayer with all three races”. The game will feature the Havok physics engine, allowing “debris [to] roll down a ramp”, as well as improved 3D graphics. Its lead designer is Dustin Browder.