I had a problem with a Windows 8 app (the „Flow“ game) which was partially broken. The app’s tile was no longer shown on the start screen, and no icon was shown when I searched for the app’s name, though Windows noted that there was „1 Application“ with a matching name – but no tiles where shown. For this reason, I couldn’t right-click the tile to uninstall it.
Thanks to MS support I learned that apps can be uninstalled manually through some PowerShell commands. They pointed me to this thread.
List all installed apps:
Remove a specific app:
Hint: Windows 8 apps are placed in a hidden folder named C:\Program Files\WindowsApps. Simply deleting (or renaming) an app’s folder will not properly uninstall it.