Here comes the Angry Birds film, but why can't a game just be a game?

Back in 2009 a Finnish company called Rovio launched its 52nd video game. Its premise was simple: players would use their smartphone touchscreen – still a relative novelty two years after the first iPhone came out – to control a catapult. Swine flu was in the news, so the enemies would be pigs. That game reportedly cost less than 100,000 to make. The numbers involved in The Angry Birds Movie, which arrives in cinemas 13 May, are rather larger.