This is a demo of Windows 10 Technical Preview, Build 9926. A little bit of the interface is different, the taskbar and there are some icons besides the Start button. And yes, the new Start menu looks great.
The main philosophy of Windows 10 is to have one operating system that will run on phones, tablets, PCs, and even the Xbox. It will work with universal apps so the developers could make one piece of software and have that software tailored to different device screen size.