Microsoft has finally lifted the veil, and anyone with an Internet connection can get a look at a pre-beta version of Windows 8 Desktop. For those who haven’t seen it yet, the new Windows has not one but two desktops. The first, which is called “the Desktop,” swoops in from the left and looks like the familiar Windows 7 desktop, right down to the little hummingbird. Any pre–Windows 8 applications – the only ones that exist on the planet, as I write this – run on that desktop. But the Desktop is missing one pretty big thing: the Start menu. To get to the Start menu, you click a rectangular area in the lower left-hand corner, causing the Desktop to swoop off to the left, replaced by a new green desktop that zooms in from the right. That “desktop” – its official name is the “Start Screen” – is a green screen covered with rectangles called “tiles” that are smaller than normal windows but larger than icons. Yes, as odd as it sounds, what was once the Start menu, a popup in the lower left-hand corner of the screen, has become essentially a separate desktop of its own – but remember, it’s a “Start Screen,” not a desktop.

A tile might start up a pre–Windows 8 application, causing another swoop as the green desktop disappears and the old one returns, hosting your application, or a tile might start up an application built for Microsoft’s new touch-friendly application platform called the “Metro” platform. (I couldn’t get anyone at the Microsoft BUILD conference to go on record about where the name came from, in case you’re wondering. Most of us smart-aleck journalist class-clown types agreed that inasmuch as the programming interface for Metro apps was designed to be quick, slim, and attractive, that the likeliest explanation was that it referred to the “metrosexual” nature of the UI. I noted that I wouldn’t have expected that sort of thing from what can factually be called the “right-wing” desktop. Far fewer people found that funny than I’d expected.)

Apps built with Metro so that they’ll run on the Start Screen (which most folks soon start calling the “Metro Desktop” will, I think, have great curb appeal – the first time you hold a multi-touch–equipped Windows 8 tablet in your hands and start playing with it, you’ll get that “Oooh, shiny!” feel. If you’re an iPad addict (as I am) and you’ve been terribly pessimistic that Microsoft could come up with a multi-touch interface that was neither a blatantly uncreative iPad ripoff, nor just a pathetic spruced-up version of Windows Tablet Edition (as I was), you’re going to be surprised. Metro’s chosen typeface is distinctive and readable while at the same time offering a cure for Arial burnout – a little like reading the Sunday New York Times Magazine. On a tablet with some horsepower, the Windows 8 pre-beta is pretty, fun, and at times I must admit that Metro is downright beautiful. (Although I do hope I’ll be able to change the pool table baize green background when Windows 8 finally ships.)

Even better, it out-does the iPad in that you can have two applications on-screen at the same time, and they’re arrayed in an appealing fashion, with one app taking a 320-pixel-wide hunk of the right or left side (that app is said to be “snapped”) and the other app – which is said to be “filled” – getting the remainder of the screen’s width. Far too many attempts at scheduling some bit of air travel on my iPad have required a mildly dizzying rapid-fire series of screen whirls as I jump between Safari, where I’m interacting with the airline’s web page, and my calendar, and I anticipate snapping my calendar or Contacts a lot as I get comfy with Metro.

Another nice touch to the Metro desktop – which, recall, doesn’t just host these new-fangled applications, it also serves as the Start menu for old-style Windows apps – is that if you know what you want to run, you can just type it right onto the screen. If I want to run Calculator and don’t want to have to search around to see if Microsoft’s bothered to create a tile that’ll start Calculator, all I need to do is type “calc” and press Enter. When Metro sees you typing, it opens up a Search field. No Windows+R needed, no clicking the Start button and trying to figure out if “Search” is like “Run” used to be. Nope, just write your request on the wall, and your wish is granted.

Now, from what I’ve said, it sounds as though the new Metro interface might sell a few zillion new PCs when it ships. Maybe, but not necessarily. First of all, writing a Metro app is as different from writing a traditional Windows app as writing a Windows app is from writing a Mac app, almost. One speaker stated that the existing Win32 and .NET application programming interfaces (APIs) had about 600,000 different “hooks” that programmers could use, but that Metro apps aren’t built atop Win32 but instead sit on something completely new called the Windows Runtime (WinRT) that has about 8,000 hooks in it. (A lot of where the 600,000 comes from is redundancy. For example, the first round of Windows APIs that needed strings only took simple ASCII strings, and in time Microsoft added Unicode support, so the APIs needed to reflect that, instantly nearly doubling the number of APIs. But even when you take that into account, it’s clear that there are large sections of the software universe that cannot and will not be converted to Metro/WinRT, meaning that Microsoft seems to think that we’ll be happy living with two desktops for quite some time, if not forever.) Will Windows programmers learn the new platform, or find it too complex, strange and new? And how many Windows programmers might just say, “Heck, if I’m going to write for a different platform, maybe now’s the time to learn Mac programming”?

Second, while the multi-touch interface is nice, very few of us in the Windows world have multi-touch-equipped hardware, and so will be using a mouse to control the Metro-centric Start Screen. Unfortunately, however, a few minutes mousing on the Metro screen will disappoint. Put simply, using a mouse on the Start Screen is painful, and I mean that literally – much of what you need to do to control Metro involves clicking exactly on a one-pixel frame that surrounds the Start Screen, and while that’s easy for big old fat fingers on a multi-touch panel, it’s an exacting process with a mouse, and if you’ve ever suffered from carpal tunnel, get ready for déjà vu. Believe me, mouse users will not be snapping their apps. I’m sorry to have to say it, but the mouse experience in Metro might be the most annoying one ever in Windows history, and that’s not going to help Windows 8 sales.

And speaking of snapping, that wonderful little two-apps-sharing-a-screen Windows 8 notion has a somewhat fatal flaw. Snapping only works on a tablet that is at least 1366 pixels wide – but have you ever used a 1366-pixel-wide tablet? I have, as I was allowed to hold for about seven minutes one of the ultra-exclusive, you-can’t-buy-one-so-stop-asking Samsung Windows 8 tablets that Microsoft gave out to non-press BUILD attendees – and although it is ultra-cool and I might even run my grandmother over to get one, I wonder if, when packing for a weekend trip, I’d end up grabbing the smaller iPad or the larger Samsung 1366. My guess is that most Windows 8–compatible tablets will be just 1024 pixels wide, obviating what I see as a significant “I’m cooler” reason to buy a Windows 8 tablet rather than an iPad. Add to that the fact that you can get a fairly nifty iPad for $750 and in contrast that I’d guess that if the Samsung tablet ever goes on sale to we members of the great unwashed that we’d end up paying roughly what Samsung charges for their 900x superlight laptop – a trifle over $2000 – and thus I’m not optimistic about how competitive Windows 8 can be. In short, no one will want Windows 8 on a mouse-based system – and no one will be able to afford a Windows 8 multi-touch-based system. And that’s a shame, because Metro’s pretty fun. Remember, though, this is a pre-beta, so there’s plenty of time for Windows 8 to get a lot better (or, sadly, worse).