Millions of players have tried to escape from Aperture Science a second time around.
Yesterday, at the Games for Change festival in New York City, Valve's big boss Gabe Newell took the stage to, one imagines, talk about Gabe Newell-ish things. In passing, however, he mentioned that the well-received Portal 2 had sold 3 million copies since its launch at the end of April.
Given that Newell didn't mention any specific platforms, as Joystiq notes, it's likely that this figure is a grand total of all copies sold across PC, Mac, PS3 and Xbox 360.
It's also interesting to note that this is likely to be one of the few completely-accurate sales numbers in the post-digital-distribution world. Market analysts like NPD can tell us that the original Portal has sold 4 million copies since its release in 2007, but that only covers boxed sales from retail - there's no way of knowing how much it sold on Steam.
Unless, of course, you were to be the CEO of the company that owns and operates Steam. In that case, you'd probably know exactly how many copies the game sold.
You know, Gabe, it'd make analysts' lives a whole lot easier if you guys just reported that sort of thing on a regular basis.