Since its release, the Google Now Launcher has only officially worked with Nexus and Google Play Edition devices. It’s not difficult to sideload the app to work on many other devices, but if you wanted it through the Play Store, you had to own one of Google’s “compatible” devices.
Google Cast for Android TV devices can now be updated a lot easier since Google has moved it to the Play Store. This is the case for both the ADT-1 and the Nexus Player, and we presume it will be the case for the upcoming Razer Forge TV as well as all the new TVs from Sony, Sharp, and Philips.
Google Cast is the software used for Chromecasting compatible apps to your Android TV device.