I don’t know if this has been posted before, and I don’t know how to post videos from the Xbox onto the computer, but I found this little glitch(I think it would be considered a glitch?) in the second level.
Okay, you have to start from the beginning, it can be done with one person but it’s easier with two. Take the skull all the way until you see Sergeant Johnson (right before you go to save the Marines when he says "we both know what they do to prisoners)
Next, betray every Marine (staying back in the room where the drones pick up that one Marine REALLY helps) Let some time pass so Sergeant Johnson doesn’t kill you.
Next, headshot him with a BR and QUICKLY drop the skull next to his body (this is important, make sure that the skull is the closest thing to him because he will pick up any close weapon and kill you)
The game won’t let him pick up the skull, so he will revive, but try to melee you and make hilarious noises. Enjoy XD