UPDATE 3-Eager fans greet 'Call of Duty' video game launch

* Fans line up before midnight release

* Game could be among top-selling of all time

* Activision shares down slightly in Tuesday trade (Adds review information, factbox link, closing share price)

By Gabriel Madway and Robert MacMillan

SAN FRANCISCO/NEW YORK, Nov 10 (Reuters) - Activision Blizzard Inc's (ATVI.O) hugely anticipated "Call of Duty: Modern Warfare 2" video game went on sale on Tuesday, welcomed by eager fans who lined up hours in advance of the release.

The first-person shooter game is set to be one of the biggest and fastest-selling titles in history, challenging records set by blockbuster releases from the "Grand Theft Auto" series. [ID:nN10327116]

This despite a dicey economic climate that is pinching consumer spending. Video game industry revenue in the United States, the world's largest market, is down 13 percent this year, according to industry tracker NPD.

But Call of Duty arrives amid high expectations and plenty of hype. Activision partnered with retailers including GameStop Corp (GME.N) and Best Buy Co (BBY.N) for more than 10,000 midnight store openings in North America.

At the GameStop store near Union Square in New York City, around 80 mainly young people lined up Monday night ahead of the launch, some for two hours.