mw 2Call of Duty: Modern Warfare 2 hit another milestone as the best-selling video game has passed $1 billion in retail sales since its launch in November.

Activision Blizzard’s record-breaking game is second only to James Cameron’s Avatar film, which also passed $1 billion and is on its way to passing up Titanic as the biggest box office hit of all time. According to BoxOfficeMojo, Avatar has generated $1.34 billion in sales so far. More people have seen the film, since movie tickets cost less than the $60 game. There’s a kind of race between the two properties going on.

But Modern Warfare 2 beat Avatar in its first five days, generating $550 million in sales. And it beat other films such as Harry Potter and the Half-Blood Prince and The Dark Knight. The surprising thing with Modern Warfare 2 is that it is a hardcore game, which by its very nature has a more limited appeal to the mass market. It just so happens to be one of the most riveting game experiences ever. It also got a lot of attention because of a controversial scene where the player participates in a civilian massacre at a Russian airport; developer Infinity Ward has since included an option to skip the controversial scene.

I’ve been playing multiplayer since November and now have a rank of Major II in the game. I’m ranked worldwide at about 3.9 millionth. There are so many people playing the game that when I took six days off for the Consumer Electronics Show, my rank dropped by 300,000. The game does a wonderful job of holding your attention for weeks and weeks, mainly by doling out rewards for extended participation.