His name is Justin May and he states that this was not a viral campaign by 343i, but instead a troll just to mess with the community (He seems like a bit of a pretentious jerk). He does not go into much detail about how he managed to pull of the beta gameplay, but talks a bit about his experience with the multiplayer.
Justin May Interview: Click Play Button
Don’t take what he says very seriously as far as his review on the experience, although he does reveal some things we have not heard before. He states that there is a weapon called the storm gun that is apparently the replacement to the plasma rifle. Also that there is a variant to armor lock (not confirmed).