So I saw this today and it looks pretty freaking awesome. I'm not going to post it, because we're friends with ATVI here, but you may still be able to find it online that hasn't been pulled for copyright by ATVI. When asked about the leak, Glen Schofield had this to say:
@CodFlufy nothing I can do about it now. But yeah it sucks. Imagine you're playing and this comes up- you'd be psyched up, right?— Glen Schofield (@GlenSchofield) October 30, 2014
The trailer features a soldier with no ammo running from a hoard of infected humans. When the soldier is finally rescued by a comrade in a Helicopter who asks "Are you bit?". I don't know about you, but I'm pretty stoaked.