Nokia (Lumia) Storyteller app for Windows 8 - why can't I download it?

[Campater]

I am a little confused about the status of the (Nokia) Lumia Storyteller app for Windows (as opposed to Windows Phone). Obviously when this first came out, it was available on the 2520 only and that was of course an ARM device. However, I noticed earlier that it now apparently also available for x86 and x64 processors - see here. Confusingly, however, when I attempt to search for this within the Windows app store, it does not appear and if I follow a link from IE, I receive an error message saying the app is not available for my PC. Baffled! :unhappy: Can anyone shed any light?