In terms of its marketplace, Windows Phone 7 has been relatively successful. It has a lot of big-name apps, partly because Microsoft has invested so heavily in getting developers to come to the platform, but also because WP7 has very close ties with one of Microsoft's other very successful platform: Xbox.
With that in mind, it should come as no surprise that Microsoft is trying to up the ante for Windows Phone 7 gaming.
First off, let's talk avatars, which get a nice addition. Your online gaming self will be able to wear things that you win in games.
Second, you'll also be able to buy virtual items to make your games more fun. Think of it like in-app purchasing, but instead of with money, with Microsoft Points.
Finally, and most important in my mind, are the additions of parental controls and improved reliability of multiplayer gameplay. The former lets you control what your child may see on the marketplace, and if you already have something a little questionable on your WP7 device, it'll be blocked when Little Billy is goofing around on your phone.
There are also 14 new titles coming, as well, including Kinectimals Mobile. You don't want your pet lion to get lonely, do you?[Windows Phone Blog]