I gave my parents a Chromecast with Google TV as a Christmas gift. Yesterday, after seeing that the Apple TV app was available, I went to the Google Play store in a web browser logged into their Google account. When I searched for "Apple TV" in the app section, there it was. I clicked the install button and then selected their Chromecast as the target device. Said it would be installed soon.If this doesn't show up in the Play store, I am going to be really ticked. I already wonder if I shouldn't have gone with AppleTVs instead of Shields due to some odd behavior.
Now, maybe the app doesn't show up in Google Play if you don't have any eligible devices linked to your account? I don't know how that works. Or maybe it shows up but it just won't let you install it.