This is my adaption of the standard slide from the Day 1 keynote of Build. I have watched some of the sessions about WinRT and came to this conclusion.( orginal slide: http://i.zdnet.com/blogs/davidburela.png )
Above the white line compatibilty is indicated. Showing C++ applications , games and drivers written for x86 will not work on every version of Windows 8. This makes me think they should really change the message "Everything which runs on Windows 7 will run on Windows 8". They should market the ARM version completely different! Imagine the disaster if "Games for Windows" don't work on Windows...
Next, it is also unclear if Desktop Applications (WPF , SilverLight OOB, WinForms) will be able to use the new WinRT API's or should keep using the ugly COM way of tapping into Windows.
What are your toughts on the windows 8 DEV story (and how it has been communicated) ?