Wow I didn't know it had been removed from the store. Better make a backup of the installer file and hope it'll last a couple upcoming iOS versions, since some major updates are in-famous for breaking apps bad... still can't get over Bioshock. Hahaha (ಥ﹏ಥ)
Probably because Sierra/Activision would sue them into oblivion. Still, given that the game still seems to work fine on tvOS and iOS 11 (not sure about the latest Android), I've no idea why it was pulled. Sierra's not responded to me as yet.