Now that the initial shock has worn off, take a look at Long Zheng's detailed run through the presentation slides on his Istartedsomething blog.
Of course there are many open questions. Here are a few that have struck me.
It appears as if Internet Explorer 9 will work in the desktop "Win7 compatibility box" (for lack of a better term), and IE10 will work outside the box, as one of the tiled applications. The demo showed IE10 working at a higher level -- on the same tier as the Windows desktop itself. Does that mean IE9 (and, presumably, other browsers) are banished to the desktop?
Microsoft swears it won't ship two different versions of Win8, but I can't imagine how it'll avoid it. The part of Win8 that we saw living outside the Win7 compatibility box appears to be highly dependent on touch. The part inside the Win7 compatibility box (once again, that's my terminology, not Microsoft's!) is touch-enabled in a very traditional way. The live tiles outside the box and the touch-to-click windows inside the box come from very different gene pools. Do office workers really want or need the live tile part outside the box? Do Windows Phone users expect to do anything relevant inside the box?
Watch Walt Mossberg fiddle with the no-touch laptop around 15:15 into the demo. Is he trying to grab the edge of the screen -- a simple process with a touchscreen -- using the mousepad? If so, his repeated swipes speak volumes for the difficulty of using a mouse in a live tile world.
Windows 8 will run on ARM tablets, and Microsoft has already advised there won't be any application compatibility guarantees -- older Windows applications won't necessarily run on Win8 ARM tablets. Fair enough. But will any Win7 apps run on Tablet Win8?
Lots of questions -- and I don't expect to get any definitive answers until PDC, er, Build, on Sept. 13 in Anaheim.
This story, "Windows 8's user interface a touching experience," was originally published at InfoWorld.com. Get the first word on what the important tech news really means with the InfoWorld Tech Watch blog. For the latest developments in business technology news, follow InfoWorld.com on Twitter.