Players of the popular Grand Theft Auto video game series have always reveled in its unique blend of beatings, shootings and vehicular mayhem.

With Grand Theft Auto 4, they are taking the carnage online, which may dethrone first-person shooters like Halo 3 and Call of Duty 4 from the top ranks of the popular Xbox Live service.

Only a few non-shooter games have ever sat at the top of the list of most-played games on the service, which debuted in 2002 and is viewed by many gamers as primarily the domain of shooter enthusiasts.

Grand Theft Auto 4 went on sale Tuesday for the Xbox 360 and Sony's Playstation 3. Critics have raved about the online multiplayer options in the game, calling it surprisingly robust for a series that has until now been exclusively a solo experience.

Up to 16 players can participate in 15 different online game types, ranging from cooperative play to cops-and-robbers team matches to free-for-alls.

The multiplayer in this game is so well implemented that I can't imagine anyone owning a copy without trying to play it on Xbox Live, said Aaron Greenberg, the director of product management for Xbox 360 and Xbox Live.

GTA is unique because it appeals to such a large audience. It will likely be the best-selling game launched all year and we expect it will drive a lot of new members to Xbox Live.

Greenberg says he wouldn't be surprised to see the game take the top spot on Live, something that would be rare but not without precedent.

Another open-world criminal action game, Saint's Row from THQ, also briefly held the top spot in 2006 while Microsoft's Crackdown rose to the number-two spot early last year.

But those games enjoyed only brief reigns atop the charts, while Grand Theft Auto 4 may enjoy long-term dominance.

The game is expected to be the biggest entertainment event of the year, with first-week sales forecast to be up to $400 million, eclipsing those of last year's Halo 3.

This has the capabilities of being more popular online than 'Halo 3', said IDC analyst Billy Pidgeon.

Pidgeon said he went online the night of the game's release and was surprised to find almost all of his friends playing in various online modes before they'd even had a chance to dive into the epic single-player story.

I think the console, even more so than the PC, has the potential to have lots of different types of games be popular online, Pidgeon said.

GTA is an important piece of that. It can lead the way online for a large contingent of players who don't play first-person shooters.

Pidgeon says Grand Theft Auto 4 is a game that bridges generations of gamers, appealing to older players who sat alone playing titles like the earlier Grand Theft Auto installments, and younger ones who often buy games mainly to play online with friends.

Michael Pachter, an analyst with Wedbush Morgan, estimates that only 40 percent of Xbox 360 owners routinely play online.

This one definitely has more for everybody than any previous game, Pachter said.