Notifications in the Google bar
If you click the notification area in the Google bar, you’ll see a summary of your recent notifications. When you click a notification, a preview of the event that generated the notification will appear in the drop-down menu. You can take action on each notification right from the notifications menu, like commenting on a post or adding someone to a circle. To navigate between notification previews, click Newer and Older.
To view all your notifications click View all. To close the notifications menu, click the notification area in the Google bar again, or click outside of the notifications menu.
Games notificationsBy default, notifications from Google+ games will also appear in the Google bar. Your notifications may display as either a coalesced collection of all new games notifications, or some games may have their own notifications displayed.
If you'd like to not see any games notifications in the Google bar, visit the settings page and uncheck the box next to "Show Google+ games notifications in the Google bar."