Google Play has come a long way. From the days when it had just applications and was known as Android Market to 2011 when it was re-organized, received a fresh coat of paint and renamed Google Play as Google sought to bring all content under one roof: entertainment (movies, TV shows and music), books and applications. Ever since then, there have been many updates that have enhanced the look/interface of Google Play and added a few features.
According to screenshots posted by Google User Interface engineer Kirill Grouchnikov, one of the members of the team responsible, there are some sweeping changes still coming. Some of those changes include a persistent search bar on top of the application with just Google Play branding as well as some animations.
A new update that is currently rolling out, 5.10.29, already brings a few of the expected changes to Google Play but it looks like Google is saving the best for last and the big update that brings everything the above screenshots show will be out later.