The gaming world braced Monday for the launch of "Halo 3," expected to help Microsoft and its XBox 360 console in its battle against Nintendo's Wii and Sony's Playstation 3.

Microsoft was to release the game in the United States at 12:01 am Tuesday (0401 GMT) and in 37 countries by the end of the week with a series of high-profile events.

"With nary a pirate, a spider or a wand in sight, day-one sales of the highly anticipated video game are expected to shatter entertainment sales records and top the biggest entertainment launches of all time," Microsoft said in a statement, comparing the event to releases of "Harry Potter" and "Pirates of the Caribbean."

"By the end of the week, fans in 37 countries will be playing the game Wired magazine recently called 'a cultural touchstone, a Star Wars for the thumb-stick generation.'"

Microsoft said it had received a record 1.5 million pre-orders for the game, and would hold midnight launch events at 10,000 retailers across the United States featuring contests and appearances by local celebrities and athletes.

Many retailers were to hold special openings for the sale, and some expected customers to queue up for the first copies of the game, which sells for 60 dollars for the basic version and 130 dollars for a premium edition.

The game developed by Microsoft and its partner Bungie Studios is the third in the Halo Trilogy, a so-called "first-person shooter" action game that has been a big success.

Halo 3 "has further mastered the art of marrying fantastic gameplay with the intangibles that make the experience extraordinary for gamers, evoking incredible emotion through its story and character development," said Shane Kim, vice president of Microsoft Game Studios.

"That emotion is at the heart of what makes this more than a game and why 'Halo' connects with its audience in the way other great stories like 'Star Wars' resonated with theirs."

Gaming review site MetaCritic gave the new game a 96 rating out of 100 and says it provides "the thrilling conclusion" to the events begun in the first Halo.

"The Master Chief is returning to Earth to finish the fight. The Covenant occupation of Earth has uncovered a massive and ancient object beneath the African sands -- an object whose secrets have yet to be revealed," MetaCritic said.

"Earth's forces are battered and beaten. The Master Chief's AI companion Cortana is still trapped in the clutches of the Gravemind -- a horrifying Flood intelligence, and a civil war is raging in the heart of the Covenant. This is how the world ends."

Analyst Michael Gartenberg at Jupiter Research said Halo 3 "will likely be a killer app," or application, for XBox 360, which has been struggling against the Playstation 3 and Wii from Microsoft's Japanese rivals.

"I've had a chance to play with a review copy for a bit and now the embargo is lifted it's safe for me to say, this is going to be a monster hit for Microsoft and it's the type of game that will sell systems, probably a lot of them," Gartenberg said.

"Halo 3 has been one of the most anticipated titles in the history of gaming and Microsoft and Bungie delivered well."

Microsoft recently cut the US price for its Xbox 360 to better compete with the Wii and PS3 and its reputation was tarnished by a design defect that Microsoft says it has fixed. Microsoft set aside a billion dollars in its most recent fiscal quarter to repair or replace flawed consoles.

Microsoft has shipped 11.6 million Xbox 360s since the consoles debuted in of 2005. But Nintendo is riding a wave of popularity and has been selling Wii consoles as fast as it makes them since sales began in November 2006.

Still, XBox 360 has outsold its key competitors in the US market so far this year, according to data from NPD Group.

David Cole, an analyst with DFC Intelligence, said the game may help Microsoft but is aimed mainly at those who already are committed to the platform.

"Microsoft's biggest challenge is to grow beyond that 'converted' base," he said.

"The buzz around Halo 3 is truly unprecedented, and while many want to take sides around the next-generation console wars, I'm more of an optimist who thinks this launch will be good for the entire industry," said David Riley at NPD.

"It's exactly what this industry needs to kick off the holiday shopping season."