Now there are two different types of applications (Modern UI and Desktop) and I'm wondering how to uninstall them now? Does the old "add/remove Application" still work?
Both Desktop and Modern UI applications can be uninstalled via the new Start Menu by opening the options bar (right click on the application you want to uninstall):
In case of a Modern UI application, a confirmation dialog appears and after clicking
In case of a Desktop application, the old
Just go to the "Control Panel" like in Windows 7 and go to "Unistall a program". This is only for desktop programs though.