its not yet a full version, so yes it has bugs. but else its great so far..
yes, it can directly use any c lib file, and as gl for example has an opengl32.lib wich exports c-functions, you can use gl.. and about any other libraries existing for c/c++.. sdl for example, too..
thats quite great, because you can for example write plugin-code in d as a dll and load it in your main engine, in c++. plugins should be save as first, and the gc of d helps there very much to easen that savety.
or you write your engine in d, and you use existing c-libraries or code. both doable. a very good features, as there is tons of c-stuff existing..
it doesn't have some serious bugs.. no language has... the implementation can have some serious bugs, though.. and as there is no final implementation yet, its still buggy, yes:D