The Angry Birds

The Angry Birds have a pretty good reason to be happy this week.

Rovio's juggernaut game franchise is showing absolutely no signs of waning popularity, with thedeveloper tweeting that the most recent release, Angry Birds Space, has racked up 10 million downloads in less than three days.

To put that in perspective, it took Angry Birds Rio -- the last game in the franchise -- a week and a half to hit that mark.

The number's impressive, but it's a bit harder to nail down exactly how much money was tied to it. iPhone players paid a buck each for the game and iPad users shelled out nearly $3, but anyone with an Android phone could get the game for free.

Also a mystery is how many iOS players paid the extra dollar for the super difficult levels in the game's "Danger Zone." More free levels will be available in the "near future," says Rovio.

Helping things along was the outpouring of critical love for the game. The changes in the game, including the new element of having to take the gravitational effect of planets into account, managed to add even more muscle to a franchise whose mass popularity was still going strong, though many agreed the basic gameplay had become a bit long in the tooth.

First released in December of 2009, the Angry Birds franchise has racked up over 700 million downloads across a variety of different platforms. The game has been arguably even more successful in the marketing field, making millions on everything from plush, stuffed versions of the birds to t-shirts and other merchandise.

Rovio is also in the process of creating 52 two-minute long Web-shorts focused on the birds, and last October hired David Maisel, former chair of Marvel Studios, to help it work with Hollywood to create a movie based on the game. A theme park is already underway.