We have already seen a Materialistic Design of Google Playstore app last week in a leak by AndroidPolice. Google has started rolling out the new build of the playstore ver 4.9.13 since last week. The improvements have been big this time with the looks and design. Below attached are few screenshots in which you can notice the changes being inherited in the new design.
In the above screenshots of the playstore pages, one can clearly notice the changes adhered in the new update and frankly speaking it feels much better than the earlier version.In other words the look of Playstore got a major overhaul.
Google has started rolling out the update since last week and we believe it should reach you in coming days.Google is also working on other apps to make it materialistic. Chrome Beta has been released in Google Playstore with new build 37 which hints that the next app update with Material Design will be Google Chrome.