This is in essence Windows 8 Service Pack 1, and that is what many people are calling it. Usually, all service packs do is change a few things under the hood with little in the way of visible changes, and as such they are not worth taking screenshots of and documenting. However, with Windows "8.1" Microsoft has made a few significant changes:

• There are a number of UI changes, some of which are subtle but some are not. This could invalidate existing training, documentation, and assistance practices, all stuff a service pack strives to avoid.
• Microsoft bumped the NT version number from 6.2 to 6.3. Most programs check this number to determine compatibility. Such a change could break them, again something a service pack strives to avoid.
• The only "official" way to get 8.1 as an update is through the Store. Ignoring the people who refuse to use the Store (of which there are many), not everyone can use it anyways. Where are these people supposed to get this update?
• DVDs containing service packs usually retain the previous product name. Not here. Microsoft now calls it Windows 8.1.

All of this sets a fairly dangerous precedent, in that future service packs will get the same treatment, effectively throwing a wrench into adopting any kind of stable platform with which to do development. The name doesn't matter. Not regarding it as a security and stability update, rather as a full OS iteration, does. Further adding to the confusion is the fact that Windows 8 has reportedly "lost" support.

But in any event, on to the screenshots.

Grudgingly, I resorted to installing Windows 8.1 from the Microsoft Store, as there really is no other way to do it without downloading a torrent or something of that sort.

No change in the splash screen. I still think that Windows logo looks dumb.

No change to the lock screen. It is still as non-user friendly as it was before. So much for "simple to use".

A few minor changes to the start screen. Live tiles are permitted to be both larger and smaller. Personally, I don't understand why anyone ever cared about these things, and I still don't understand why they do now.
It's not visible in this screenshot, but there is also a plainly visible arrow "button" (really just a circular image that acts like a button) that brings you to the All Apps page. Previously this functionality was only available through a right-click context menu on a live tile. Baby steps.

No improvement here, this list is still permitted to extend for miles, and there's still a redundant list of Metro applications in the front. At the very least, these should be placed at the back of the list where they are out of the way, but of course Microsoft wants to force users to use their bastardized "new" Metro apps.