What was once a humble Finnish game about launching birds at pigs with slingshots has quickly become the insanely popular Angry Birds. We visited snowy Helsinki to chat with Rovio CEO Niklas Hed about the game’s careful design and mechanics, how it turned into a worldwide addiction, and what’s next for Angry Birds. See an early prototype of the game, and enjoy a rare opportunity to watch Rovio’s head designer Jaako Iisalo create a level.