"In Google Reader Play, items are presented one at a time, and each item is big and full-screen. After you've read an item, just click the next arrow to move to the next one, or click any item on the filmstrip below to fast-forward. Of course, you can click the title or image of any item to go to the original version. And since so much of the good stuff online is visual, we automatically enlarge images and auto-play videos full-screen," explains Google.
The interface is optimized for posts that include images and for short blog posts. You can use keyboard shortcuts to navigate to the next post or you can start the slideshow view to only look at the images and headlines.
I was disappointed to see that Google Reader Play doesn't show your subscriptions. It only shows a list of recommended pages and Google uses your actions (starring, liking or sharing items) to improve the recommendations. If you want to read your subscriptions in Google Reader Play, use this URL:
http://www.google.com/reader/play/#stream