Halo 2 took nearly three years to develop--but it was apparently worth the wait. Microsoft has announced that sales of the sequel to the Xbox's flagship game have exceeded 5 million copies since its highly publicized release on November 9.

　　When combined with the sales numbers from the original Halo, which launched alongside the Xbox in 2001, the Halo 2 figures put the franchise's sales at a whopping 11 million units--with the holiday retail season still not over.

　　Also, Halo 2 online play has been rampant. Xbox Live support reports the game has garnered more than 28 million hours of online play, already more than any other Xbox Live title to date. More than 900,000 unique Xbox Live gamers have experienced Halo 2 online at an average of over 90 minutes per session.

　　The game's launch spurred more than 1.5 million preorders, several midnight sales events around the globe, and first-day sales of more than $100 million. Its release, along with a shortage in PlayStation 2 consoles, has also boosted Xbox console sales during the holiday season.

　　For more on Halo 2, check out our full review of the sci-fi shooter.