This is a tech demo called Infiltrator that the people at Epic Games have been showing to reporters and developers all week at the Game Developers Conference this week in San Francisco. Is it a game? Or just a way to show off what the Unreal Engine can do for next-gen video game graphics? I'm not sure. The video was supposed to go live everywhere at noon ET today, but, as you can see, it leaked early. We'll have more on this and Epic's other GDC 2013 showpieces in the next hour or so. Epic is the studio behind the Unreal Engines, which power many of the industry's top games, including the Mass Effect series and the Batman Arkham games. Epic also makes Gears of War and Infinity Blade, pushing their own engines to the limit.