Microsoft have updated the Windows 10 Movies & TV app (called Film & TV app, or Films and Telly as it should be called in English). The new version (3.6.1536) adds a new dark theme to the app which you can the option in the settings section of the app.
In the release notes Microsoft also say that there are additional keyboard shortcuts in the app. I really like the dark themes of Edge, Groove and the Movies & TV app and it would nice it you could switch the whole OS between light and dark. Maybe that could be an option with Redstone.