Read the entire article in Techcrunch
“Back in February 2009, Inedible Software released Shotgun [iTunes Link] after the company’s co-founders met in an iPhone development class at Stanford. The idea was simple: it’d turn your iPhone… into a shotgun. Users “pump” the shotgun by jerking the iPhone back and forth (vertically or horizontally), then “fire” by either tapping the screen or jerking your hand upward to simulate recoil. It was a fun toy, and something that Inedible hoped a few people might download.
Over 7 million downloads later, the company decided it was time to take things up a notch. Enter Shotgun Duel. Same idea, but with better graphics, improved gesture detection, and best of all: multiplayer dueling.” – Excerpt from Techcrunch