The OCaml download page is announcing that there is four Windows ports available: Cygwin, Mingw, native Win32, and native Win64. However the latest one is in fact not available and must be compiled from sources only.
Given that the Windows/x86_64 port has been done since a few years, I was wondering why the binary distribution process is not automated? Is there any technical restrictions or bugs with that Ocaml port?
I don't think is a matter of technical restrictions but of the nature of OCaml project.
It is a project born for the opensource world and in this context compiling something by yourself is just normal.. I don't think they invest so much time in preparing binary distributions for people since they usually download and compile it.
Infact using the MSVC port is nice if you plan to use plain OCaml but if you want to include external libraries or using advanced features you'll go just crazy.
I started with MSVC port until I needed things (like menhir) that made me think about using a complete distribution package like godi when I realized that no support was given to binary distributions..
OCaml team doesn't have enough resources to provide windows builds and testing themselves (afair there is only one person there who touches windows OS at all), hence the result. This is an area where community could help, but still nobody stepped in. Maybe ocaml-installer will materialize in something.