The Google Play Store now allows you to preregister for a select upcoming line of games and apps.
The first game to support this function is Terminator Genisys : Revolution by Glu Mobile. There is no price or release date but expect to get it on the same date that the movie will be premiered, July 1st.
Google will allow a select line of publishers to feature this function for their games and apps before they are made available to purchase. The pages containing these apps/games will look like a normal app page but instead of the buy button, you will see a preregister button.
Pre-registration doesn’t make you obliged to buy it, you can always not buy it if you change your mind when it comes out. It is totally free. The only advantage is that those who preregister will receive a notification when the game/app is made available to purchase on the Play Store. We'll just pretend we won't snap up whatever we pre-registered for when we do get the notification.