I’m planning to port my Unity game Stick 'Em Up 2 to tvOS as soon as possible, and if there’s an alpha or beta of tvOS support in Unity I’d very much like to participate.
The game is running on iOS (and Windows/Mac/Linux/Android) already with support for game controllers, so I think it’ll make a good test project. I actively report Unity bugs with good minimal test cases.
We already started closed preview group for Apple TV support for people who have access to the devkits. If you get one please ping me via PM and I will add you to the group.
Though we don’t have dates to share yet when previews or betas will be available to wider audiences.
You can have more than 200 MB while game is running, that just means that some content might be trimmed by OS between game sessions. So it’s more important to have game as set of dynamically loaded building blocks, rather than hard requirement to setup everything as separate levels. Please check out our support for On Demand Resources: Second preview build for iOS 9 On Demand Resources and App Slicing support - Unity Engine - Unity Discussions
Apple sends mail out to developers who have titles with moderate or interesting success. They’re not targeting people who don’t already have games on iOS. If you haven’t been contacted it’s best to wait.
Too late (at least for the email I received a few days ago) :
Apple TV Developer Kit
We want to give you the chance to test your tvOS apps and experience them on a big screen before the new Apple TV is available to customers later this fall. Register by September 11, 12:00 p.m. PDT to get an Apple TV Developer Kit.
How does one PM you on these forums? I have not seen how to do that. I do have a dev kit and have been updating a game to Unity 5. Would love to be able to test it on the new Apple TV.