The Windows 8 UI (former called “Metro”) is a new user interface featuring a Start screen that replaces the start menu of older Windows versions. Metro is not a start menu, because no start menu exists in Windows 8.
Do you actually know anything about Windows 8 or is it just funny to post wrong things in a forum?
The expression “Metro style applications” refers to a set of API’s called Windows Runtime (or WinRT for short) and is not just a user interface, but a complete API comparable to iOS and Android. It was made for a seamless experience on both the old Intel architectures and the now common ARM devices.
As far as me calling it Start “menu”, agreed, it’s Start “screen”. But essentially that is semantics, and a bit of a [pf]un.