First of all, the most amazing thing they could do, separate the games from the stream totally: unlike Facebook, games has their own tab and stream, completely separated from the home tab and stream.
Is the last tab on the top, next to Circles. In the left side of that tab you’ll see the way to organize available games. Featured, which are the ones Google promotes. All Games shows the complete list of games. And the notifications are the last option.
Also, as I said, Game Stream is separate from your home stream, and is located at the bottom part of the Games Tab.
Apparently, games are already available to everybody, or at least to a lot of users. Until now, I’m actually playing since I know that I won’t spam streams or get spammed by these games.
Via | The Official Google Blog