The Store application rounds ratings to the nearest half-star. App Highlights shows the ratings without any rounding.
You can download App Highlights from Store (formerly Marketplace). When App Highlights is installed, it is shown in the app menu on your phone.
Most probably the application you are trying to view or install is not available in your country.
Check that the country in your Region format (Settings > Region+language) matches the address you have registered to your Microsoft Account ID. This will ensure you only see content targeted for your country.
With App Highlights, you can browse selected content from Microsoft Store and Windows Marketplace. You can save your search results for further use, and set preferences for some of the content shown to you. Actual purchasing and downloading content is always done via MSFT Store / Marketplace itself.
The applications in App Highlights are hand-picked from the Windows Phone Marketplace. The application data is updated from the Marketplace regularly, but might be temporarily outdated. Please try again in a few days.
This feature is not available on Lumia phones with less than 257MB of memory.
This is the application that is currently shown on the live tile. It is provided for easy access to the currently featured app. If you don't have the live tile pinned to your start screen, this is irrelevant.
The latest version of the app is 2.1.1. It supports Lumia phones with Windows Phone 7 and Windows Phone 8.
Please make sure that you have the correct region set on your phone. Go to Settings > region+language, and select the correct region in the system locale field.
Not currently, but maybe in the future.