If you know how to use visual studio you can convert a contruct game to a metro app in about 60 seconds. Start a new javascript project then import jquery-1.7.1.min.js and c2runtime.js files into the js folder.
Add all your images to images folder and create media folder if you need it. Then copy the code over from index.html into the default.html file in the project, some small modifications are required in the html for example you have to point all javascript src files to /js/ like this src='/js/jquery-1.7.1.min.js' because you cant use scripts from URLs they have to be local sourced
Then build/run the project and your game is now a metro app :) it works great.
A built in metro exporter in construct 2 would be great though so im looking forward to that :D