It's happening. The Google Play Store is picking up an update to version 5.0.31, crossing over the 5.0 border for the first time and bringing a pretty comprehensive redesign within Material Design guidelines. It all starts with a new "flatter" Play Store icon and continues throughout the app with bold colors, small useful animations and better application of shadows and coloring.
You'll immediately notice new animations for the slide-in panel and associated hamburger button (which turns into a back arrow), as well as changes to the way the "what's new" section of apps listings is highlighted and properly displayed. App listings themselves haven't changed dramatically — a lot of that came in the last update — but everything around them in the search results and installed apps list has come up to speed.
Beyond the aesthetic changes, the new Play Store feels really snappy, and we've yet to notice any chop, slowdowns or loading screens. Who knows how much of that is just animation trickery and how much is real improvement, but it certainly feels better. It's a one-two punch of design and function that has us really excited for the future Material Design updates of other Google apps.
We've worked up a quick gallery of screenshots from the new design that give you a good look at the changes. If you're not seeing the update on your own phone just yet, it's best to be patient if you can and let it roll out to you — you'll get it soon enough, and avoid problems in the future by not having an oddball version on your phone.