The maximum size of applications for the fourth-generation Apple TV is limited to 200 megabytes.
However, as the British edition of develop clarifies, heavy programs will be able to safely use the missing content from iCloud. In other words, after installation, one or another resource-intensive application will constantly access the “cloud”: upload something to local memory, delete something from there.
How this will affect the performance of games and applications is not very clear yet. On the other hand, given the prevalence of high-speed cable Internet connection, most likely, this is unlikely to become a UX problem.
In addition, judging by the presence on the Transistor platform and the announcement of Galaxy of Fire 3, which clearly weighs more than 200 MB, the developers of these games have already solved this problem, no matter how difficult it may be.
More information about working with tvOS can be found here.
A source: http://www.develop-online.net
You can learn about the details of working with tvOS at White Nights Moscow 2015, which will be held very soon – October 13-14.