Here's what I've found so far:
" If your app includes an ARM or a Neutral package it must support Direct3D feature level 9_1. If your app does not support ARM it must support the minimum feature level chosen on the Store portal. "
" Developers looking for maximum performance for their games and other graphics-intensive apps can use the power of Microsoft DirectX 11. "
This is nice:
" Windows 8 scales apps to ensure consistent physical sizes for UI elements regardless of the pixel density of the screen. As a developer, your work is minimal?just provide scalable resources and Windows takes care of the rest. "
This is what I believe to be the best and most defining feature of windows 8:
" Tiles are connected and alive "
" Through tiles on the Start screen, apps are alive with activity and can deliver vibrant content, even when they?re not running. Using live tiles, your app can provide useful, at-a-glance data to the user, while minimizing battery usage. Windows Push Noti?cation Services enables your app to receive messages and send them to your app?s live tile or provide a noti?cation to the user. "
Ehh, this doesn't sound good for C2:
" Developers looking for the best possible performance on Windows 8 can use Microsoft DirectX 11.1 with C++. "
But they seem to care about HTML5...
Visual Studio Express 2012 for Windows 8 provides access to an extensive library of application templates to streamline and accelerate app development.(plug-in, perhaps? or still useless without WebGL?)"
Here is the heart of it, as Ashley has repeated many times:
" DirectX graphics are at the core of Windows 8. DirectX enables your full-screen Metro style apps to deliver smooth, ?icker-free action whether you created them using HTML5 or XAML. No matter which model you choose to develop your Metro style app, if the hardware supports it, your app will always be hardware accelerated. "
So, it appears to me anyways, that the real question regarding whether or not C2 game developers can be competitive in the Windows 8 store, is
"is it possible to integrate C2 projects with Direct X in an timely and effective manner?"
Much of the above facts can be read through, alongside more details, at Microsoft Windows Apps Site