Everyone should watch this one. It has way more stuff then the one I posted.
-new perk is Mule Kick
-gas zombies teleport short distances
-spas-12 pick-up gives you the spas-12 (useless much......)
-there's something about players getting infected and they attack you
-wave gun get's split into two
-Area 51 is a holding area (as stating in the achievements) and my guess is you face endless waves of zombies, without rounds, until you can get back to the moon via the teleporter
-some sort of pyramid structure is shown, seems alien!!!!
i believe wen u buy the mule kick perk, a random weapon powerup appears. i mean it makes perfect sense