Hugh Pickens writes writes: "The 50 million individuals who have downloaded 'Angry Birds' play roughly 200 million minutes of the game a day, which translates into 1.2 billion hours a year, more than ten times the 100 million hours spent creating Wikipedia over the entire life span of the online encyclopedia. Why is this seemly simple game so massively compelling? Charles L. Mauro performs a cognitive teardown of the user experience of Angry Birds and concludes that the game is engaging, in fact addictive, due to the carefully scripted expansion of the user’s mental model of the strategy component and incremental increases in problem/solution methodology. The birds are packed with clever behaviors that expand the user’s mental model at just the point when game-level complexity is increased and Angry Birds is full of little mysteries. For example, why are tiny bananas suddenly strewn about in some play sequences and not in others? Why do the houses containing pigs shake ever so slightly at the beginning of each game play sequence? Why is the game’s play space showing a cross section of underground rocks and dirt? One can spend a lot of time processing these little clues, consciously or subconsciously. "Creating truly engaging software experiences is far more complex than one might assume, even in the simplest of computer games," writes Mauro. "You go Birds! Your success certainly makes others Angry and envious.""