Just wanted to add a shoutout to WinJS for posterity, with which I built a Windows 8 app that I had published to the Windows Store for a brief period of time. Then they open-sourced the UI part of WinJS and decided it was just a web framework instead of an officially supported method for building Windows apps iirc, which was the end of my foray into the Windows store.
https://github.com/winjs/winjs