Nobuna is a listening game designed to help anyone enjoy learning the English language. You play and learn as you listen. You simply watch and listen to the videos and then you fill in the blanks in the provided script. You have the opportunity to watch the videos as many times as you need.
I'm not too sure about the 'game' label - it's basically just filling in the gaps, and not quite as exciting as the promo video suggests. However, there's a good range of videos (no 'Business' category, unfortunately) and the 'Hints' feature is a good idea.