Apple disapproved of the game's “mature content.”
Unpleasant Horse is the first title from the recently unveiled PopCap offshoot 4th and Battery, and is a game about a sociopathic horse who bounces on top of clouds and other flying ponies. The ponies are then "sent plummeting to a gruesome, bone-chewing demise, thanks to an unfortunately placed series of meat grinders on the ground below.” Sadly, Apple does not approve of that "mature content," and has rejected Unpleasant Horse from the App store.
After learning of the rejection, 4th and Battery responded via Twitter and says that they still hope to release the game on the usual Apple platforms.
“WTF? Apple rejected Unpleasant Horse cuz of ‘mature content’? We thought horses dying in meat grinders was wholesome family entertainment! We’re appealing, though (with a higher rating) and we’ll hopefully have good news for y’all soon!”
The Tweet has since been deleted, and there are two interesting aspects to the story. For starters, Apple clearly isn’t afraid to reject games from large developers, and secondly, Apple has evidently formed their own version of the ESRB for the app store, and they're not afraid to exercise that authority. That may or may not be a good thing for the industry, but I'll let you form your own opinions on the matter.
Source: PC World