The video game - Halo: Reach - was released on Tuesday and it sold over 330,000 copies in Britain alone, The Sun reported on Friday.
The game casts players as genetically-enhanced marine battling to defend the human race from aliens.
The huge sales make the game one of the biggest entertainment releases ever, though it it is available only for Microsoft's Xbox 360.
Microsoft Game Studios chief Phil Spencer opined the video game will help reverse a recent dip in sales in the 40 billion pounds games industry.
"Halo: Reach is the biggest game Microsoft has ever released, and has already surpassed every game, movie and entertainment launch this year.
"Every major instalment has grown in popularity, making the Halo franchise one of the most popular entertainment properties in the world.
"The figures tell me that gamers are out there, and are willing to buy the great experiences. The industry is in a healthy state," Spencer was quoted as saying.
Published 17 September 2010, 06:21 IST