A leaked version of Windows 10 build 9901 shows some interesting new features. The development of this new (well ..) OS is going strong, the first screen-shots have been posted at SuperSite for windows. The build introduces an improved version of Cortana, a unified Store app, a new Settings app, new visual styling, and more, see after the break.

The biggest new feature since the recent technical preview is the addition of Cortana. A video demonstration leaked earlier this month, but the build itself shows how Cortana sits at the top of the search interface for Windows 10, responding to text and voice commands. It's all very similar to the Windows Phone version, as you’d expect, with access to the notebook, reminders, and interests. It's not entirely functional, but it's a very early look at the digital assistant in Windows 10 so the final version will likely change significantly. 

Elsewhere there's also a new Xbox app. It appears to act as a gateway to the entire Xbox ecosystem, including access to achievements, friends lists, activity feeds, and the Store. Microsoft notes that it's an early preview of the app, so it may well include SmartGlass integration in future. It's also a first glimpse at how the software maker is designing its native Windows 10 apps, and the calculator app has been updated in a similar way. 

• A more fleshed-out version of Cortana, Microsoft's voice-activated digital assistant, complete with a search field right in the taskbar.
• A unified Store app that combines "apps, games, music, and movies & TV" with "document-style vertical navigation" (meaning, hopefully, no more horizontal scrolling).
• Revamped Xbox and Photos apps.
• A new Settings app that "shows how Microsoft may replace both PC Settings and Control Panel with a single UI." Microsoft replacing Windows' weird mish-mash of new and old control panels seems long overdue.
• Plus some visual styling changes, including a black taskbar, new buttons on Modern UI window frames, and a handful of fresh wallpapers.

Paul Thurrott has posted a screenshots from build 9901 of Windows 10