"Halo" not only passed the opening-day boxoffice record of $59.8 million set by Sony's "Spider-Man 3" in May, its one-day haul Tuesday also vaulted it ahead of Spidey's three-day opening-weekend record of $151 million.

However, the unit sales of "Halo 3" were overshadowed by those of J.K. Rowling's novel "Harry Potter and the Deathly Hallows" when it was published in July. "Hallows" sold 8.3 million copies in the U.S. during its first 24 hours. Microsoft did not supply unit sales but did note that more than 1.7 million copes were preordered.

The game would have had to have sold more than 2 million copies its first day to hit the $170 million mark. Game prices ranged from the standard $60 edition to a $130 Legendary edition with a helmet-shaped case and two bonus discs.

Given the hype and the fact that 10,000 stores opened at midnight Monday to begin selling "Halo," the launch was expected to be huge. But retailers are suggesting that "Halo" could be the biggest video-game seller ever.

"The initial demand we've seen for 'Halo 3' has been astounding, and the game is on track to become the No. 1 gaming title of all time," Best Buy movies and games vp Jill Hamburger said.

Some early purchasers of the special limited edition did complain that the packaging resulted in scratched discs. Microsoft says its disc-replacement program would cover any damaged limited-edition discs at no charge through Feb. 1.

Industry observers grumbled that likening a video game, retailing for $60 or more, to a film that cost $12 at most to view in theaters makes for an inexact comparison, especially given the secondary markets, where "Spider-Man" will generate even more revenue.

But if the "Spider-Man" snub wasn't enough to annoy Sony, analyst expectations that "Halo" will spur sales of Microsoft's Xbox 360 at the expense of Sony's PlayStation consoles sure did.

"It's certainly going to create a better environment for Microsoft this holiday," said IDC game analyst Billy Pidgeon, who projected that "Halo" might end up driving as many as 1 million additional Xbox 360 hardware sales before it's all over.

" 'Halo 3' has become a pop-culture phenomenon," Microsoft Game Studios vp Shane Kim said. "Not only is 'Halo' setting sales records, it's also redefining entertainment."

This week, Boston-based analyst group Compete said that as many as 300,000 Xbox 360 hardware units might have been sold in the past month solely because of the pending arrival of "Halo." The group added that Microsoft is well positioned to reach a "tipping point" in terms of U.S. sales for the holidays.

"Halo 3" has been Microsoft's ace in the hole for several years, and the company is spending just less than $50 million in marketing -- including traditional ads and promotional partnerships -- in the U.S. alone.

"Halo 2" brought in $125 million its first day.

Microsoft also is counting on "Halo 3" as a key component of its online Xbox Live strategy, which allows multiple players. "Within the first 20 hours alone, we've seen more than a million Xbox Live members come online to play 'Halo 3,' " Kim said.

Pidgeon noted that there are plenty of soon-to-be released titles with great buzz in the gaming community.

" 'Halo' could be just the first of many events in the coming months that really spike sales," he said. "You have games such as 'Smash Bros.' for the Nintendo Wii as well as 'Rock Band' and 'Guitar Hero 3,' so we'll see how long 'Halo 3' remains on top."