Unreal Engine 4.1.0 MacOSX | 2.05 GB

This source code is the Unreal Engine 4 which is in the GitHub repository page with restricted access EpicGames. At the moment it is one of the newest and most promising engines. Details can be found on the official website unrealengine

The code of the engine you can use in Xcode 5.1 or MS Visual Studio 2013, detailed information can be found in the file README.md lying inside the archive.