Which company published the original Angry Birds game at launch?

Chillingo published the original Angry Birds game at launch.

Rovio Entertainment developed Angry Birds, but it partnered with the British publisher Chillingo for the game's original iOS App Store release in December 2009. That distinction matters: Rovio was the Finnish studio that created the game, while Chillingo handled publishing and distribution for the initial iPhone and iPad version. The game is therefore commonly credited as “developed by Rovio, published by Chillingo.”

Angry Birds began as a physics-based puzzle game in which players used a slingshot to launch birds at structures occupied by green pigs. The concept grew from designer Jaakko Iisalo's sketches of angry-looking, legless birds. It initially attracted limited attention, then surged after being featured on the UK App Store in February 2010 and later reached the top of the U.S. paid-app chart.

Rovio subsequently self-published versions for other platforms, which can cause confusion about the publisher. Electronic Arts also acquired Chillingo in 2010, but that happened after the original Angry Birds launch. EA was not the publisher credited for the game's initial release.