Crytek is said to have used the Apple Worldwide Developers Conference last week to show off a new tactical action game for iOS called The Collectibles.
In the officially unannounced game, player command a squad of five members through a war-torn environment from an overhead perspective.
Demoed by developers from Crytek Budapest, The Collectibles is said to let players use a touch-based navigation and cover system, but also seamlessly transition to the D-pad and physical controller buttons.
Apple hasn't announced which third-party manufacturers will build peripherals for the iPhone, although a Logitech controller peripheral for iOS 7 appeared to leak earlier this week. The peripheral is said to fit around an iPhone 5 and feature a thumb stick and five buttons.
It was reported in April that Apple also plans to develop its own official iOS gamepad.
Apple chief executive Tim Cook said last week that iOS 7 will mark the biggest evolution of the company's mobile operating system since it debuted in 2007 - check out a series of iOS 7 images demonstrating its functionality.