NEW YORK (CNN/Money) - How big is "Halo 2"? Pre-orders for the game topped 1.5 million copies. And hundreds of thousands of walk-up sales will push its day one sales total to at least $100 million.

"I'm calling a $100 million day on 'Halo' today," Peter Moore, vice president of Microsoft's games division, said at a Harris Nesbitt investment conference Tuesday in New York.

How big is "Halo 2"? Gary Cooper, an analyst for Banc of America Securities, expects the game to sell upwards to 3.5 million copies by Dec. 31. In an October note to investors, Cooper said the release of "Halo 2" could be "the event of the year" -- despite the fact that "Grand Theft Auto: San Andreas" is likely to sell more total copies.

Cooper's claim seems to be proving true. Moore said Tuesday that one retailer sold 8,500 copies of the game in just 11 minutes. Another, he said, sold 200,000 units by daybreak Tuesday.

How big is "Halo 2"? When the clock struck midnight, some 7,000 toy, video game and electronics stores around the country opened their doors and welcome thousands of eager players. In New York's Times Square, the Toys R Us flagship store hosted a massive launch party, complete with celebrity guests.

About 1,500 people wrapped around the block waiting for a copy of the game -- and another line had formed by the time the store opened Tuesday morning.

With more than 5 million copies of the original game sold, Microsoft has good reason to throw such an elaborate party. "Halo: Combat Evolved " made the Xbox cool. It's arguable, in fact, that without "Halo," Microsoft might not have succeeded in the console market.

The Master Chief continues the fight with the Covenant in "Halo 2".

Now, the company is looking for "Halo 2" to take the Xbox to even greater heights. For more than two years, Microsoft has been carefully building the hype for the game. While demand for "Halo 2" began as soon as most people finished the original game, the PR machine kicked things into overdrive in August 2002.

That's when Jason Jones, head of Bungie Studios (the Microsoft division that made both games) gave one of the greatest hype-filled quotes the industry has ever seen: "Halo 2 is a lot like Halo 1, only it's Halo 1 on fire, going 130 miles per hour through a hospital zone, being chased by helicopters and ninjas ... And, the ninjas are all on fire, too."

Creating too much demand for the game has a downside, though. Last month, a pirated build of "Halo 2" appeared on the Internet.

The release of the highly anticipated 'Halo 2' is being compared to a movie opening. CNNfn's Mary Snow reports. Play video (Real or Windows Media)

And despite a sticker on the game's box urging retailers to not sell copies until Nov. 9, some stores chose to ignore the embargo -- leading to a feeding frenzy on eBay this weekend. The collector's edition of the game, which will retail for $55, was selling for as much as $265.

Microsoft is hoping to keep that momentum going once legitimate copies go on sale -- and has spent the last several months doing all it can to incite gamer hysteria. In July, the company began running "Halo 2" trailers before major motion pictures. It also wooed the hard-core gaming audience with an online, alternate-reality game, which proved to be an enormous success.

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It's a costly gamble, but one with big stakes. In 2003, video game industry sales topped $11 billion in the U.S. Microsoft (Research) has been steadily gaining ground in the industry, but still has a long way to go before it's on the same level as Sony (Research). There are 9.8 million Xboxes in homes around the country, compared to 24.9 million PlayStation 2s.

"Halo 2" is about as safe a bet as it can make, though. Over the past three years, the first "Halo" has never fallen out of the list of Top 10 sellers for the Xbox. And it held on to its original $49.99 price for a remarkable 24 months after release, dropping to $29.95 in November 2003. Analysts expect "Halo 2" to sell approximately 10 million copies globally.

The sequel will not only continue the story laid out in "Halo", it will fulfill the top player demand from the first game: online play. Gamers will be able to compete against each other via Xbox Live -- which should see a big spike in subscribers, putting even more money in Microsoft's coffers.

Reviews for "Halo 2" have been overwhelming so far -- averaging 97 percent, according to GameRankings.com, which compiles reviews from Web sites and offline publications.

Some of that is the hype that comes with any highly anticipated release -- most reviews tend to downplay the rather frustrating ending -- but the game is genuinely entertaining, engrossing and an improvement over its predecessor in many ways.

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So how big is "Halo 2"? Big enough that even grocery stores were taking pre-orders for it in the weeks leading up to the game's release.

I noticed this last month when my wife sent me on a mission to pick up dog food and yet another bag of Halloween candy (previously purchased bags had "mysteriously disappeared"). As I walked through the doors of my friendly, neighborhood Shoprite, the sign was there on the door -- "Reserve your copy of 'Halo 2' here!"

Granted, grabbing one of the year's hottest video games along with a pound of ground beef and a jumbo bag of Cheetos might seem a little odd, but it does serve to underline the growing importance of the video game industry.  

Chris Morris is Director of Content Development for CNN/Money. Click here to send him an e-mail.