Take-Two and Rockstar proudly boasted that Grand Theft Auto IV was the biggest launch event yet in the history of modern interactive entertainment, thanks to blockbuster sales of 6 million units (ringing up $500 million USD at cashiers) across multiple launch territories in just one week.  Immortalizing of such details was initially limited to the publisher's press releases (and of course news outlets), but now GTA IV's first day sales performance officially makes the Guiness World Records history books.

For selling 3.6 million units and earning $310 million USD on day one, GTA IV will be honored with both the "Highest Grossing Video Game in 24 Hours" and the "Highest Revenue Generated by an Entertainment Product in 24 Hours" honors in one fell swoop.  Those are some serious achievements right there, handily beating the previous title holder, Halo 3, which earned $170 million USD on launch day.

While GTA IV is selling like hotcakes, analysts still caution that its lifetime sales will potentially be lower than those for its predecessor, GTA: San Andreas.  Lifetime-to-date sales of the PS2 entry currently stand at around 21.5 million units.  A key reason for this scenario would be the natural decline in sales following a title's first week on the charts; indeed, Chart-Track today confirms that despite remaining top dog in the United Kingdom, second week sales for GTA IV in the PAL region were already 77 percent lower than they were during launch week.  Of course, we don't expect to GTA IV to be limping past pole position, and thus far it's the Xbox 360 version of the game pulling the cart.  Will the PS3 version catch up anytime soon?  Either way, GTA IV remains a winner.