It’s no secret that Epic Games has established a very avid relationship with Microsoft, producing such exclusives as Gears of War and Shadow Complex – both very high sellers for Microsoft’s system, the Xbox 360. However, it shouldn’t come as any surprise that Epic would proclaim themselves as the “unofficial engine” of Project Natal, Microsoft’s upcoming motion-sensing device.

When speaking to Official Xbox Magazine UK in an interview, Mark Rein Vice President of Epic Games talked about the many ways that Unreal technology could be implanted with Project Natal, even going as far as to call it the “unofficial engine” of Project Natal.

“We are going to work with Microsoft to make that available to Unreal Engine licensees who want to make Natal games,” Rein said. “So, if you want to make a game on Natal, you want to get a big head start and use the same tech as Microsoft, come talk to me. We are the unofficial engine of Natal, or maybe the official, I don’t know. In other words, we consider ourselves the ‘economic engine of Natal.’ You want to make money with Natal, come talk to us, we’ll help you.”

Let’s do the math. Natal + ideas = Unreal Engine usage. Sounds good to me.

According to Joystiq, when questioning about Shadow Complex’s pricing, Epic Games programmer Rob McLaughlin commented saying that it would likely not see price point below $20. Joystiq “grilled hm for more info” , but didn’t accomodate them.

Don Mustard along with Cliff Bleszinski, lead game designer on the Gears of War titles, are currently busy working on Epic Game’s first arcade title Shadow Complex – announced earlier at Microsoft’s E3 keynote.

During the Microsoft keynote, Epic Games revealed their upcoming title Shadow Complex, which is the developers first arcade title, coming exclusive to Xbox Live arcade.

The game combines the best of old-school side-scroller design with modern, cutting-edge gameplay and incredible high-definition graphics. Collect power-ups, discover new abilities and evolve your character into a force of destruction as you explore an original story set in the world of Orson Scott Card’s best-selling novel, Empire.