The Far Cry C++ MOD SDK is a source code release of the CryGame.DLL. It is the ultimate creation bundle for modders- everything you need to make a full FarCry Total Conversion and create a brand new game using CryEngine is now available. The game DLL sits on top of everything else, so you can access all other subsystems (physics, input, AI, sound etc.) from within the game source code through the supplied interfaces. Please read the C++ .pdf documents included in the SDK for more information.
You can grab the download at FileShack!