Google is escalating its challenge to Facebook by expanding its fledgling Google+ social networking service into games — allowing people to invite each other to play games, and trumpet their high scores to their Google+ Circles.

Not surprisingly, given the strength of the casual-games industry in the Seattle region, local developers PopCap and RealNetworks’ GameHouse division are among the companies with games in the initial rollout, with Bejeweled Blitz and Collapse! Blast among the first wave.

Some of the initial Google+ games.

Of course, anyone who spent hours absorbed in Pac-Man on the Google home page last year knows this technically isn’t Google’s first foray into games. Frankly it’s too bad the company isn’t including Pac-Man in Google+ rollout. Probably a licensing issue, or something like that, but it feels like a missed opportunity. (It’s still available here, by the way.)

Angry Birds is in Google+ Games, of course, as is Zynga Poker, but the initial rollout doesn’t include Zynga’s hit Facebook games, CityVille or FarmVille, despite an investment by Google in Zynga. TechCrunch speculates that those games may be exclusive to Facebook under its Zynga deal.

In his post announcing the move, Google’s Vic Gundotra sought to pre-empt the inevitable concerns from people who have had Facebook game notifications take over their feeds in the past. He promised that “your circles will only see the updates when they’re interested in playing games too.”

“If you’re not interested in games, it’s easy to ignore them,” he said. “Your stream will remain focused on conversations with the people you care about.”

Google says the rollout will be gradual, in the form of a new games tab appearing in the Google+ menu. We’re not seeing it in our Google+ yet, but if anyone has given it a try, let us know your impressions.

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