I'm pretty sure it's the Xbox360 emulator Microsoft has been working on. They're going to give it to us PC gamers for free because they realized they've treated us so terribly in the past. It'll have full Steamworks support, rerouting achievements and matchmaking through the appropriate Steam service.
Can't wait!
If I remember correctly, wasn't the original Gears PC port kind of bad? Like, poorly optimized (which is insane for an Unreal engine game), really glitchy, and broken multiplayer to boot?