I dunno...
First of all, the opening dialogue needs some serious touch-ups. The Master Chief is telling Cortana "I will keep it on auto-pilot until you are ready to return." What's going on here? Isn't Cortana the autopilot? If she left with the Master Chief, why is she talking to him over the radio? I don't get it.
Also -- I'm not a severe Halo-phile, so correct me if I'm wrong -- but I'm pretty sure that the Chief can't do an atmosphere entry without a ship or a shuttle.
Also, while the fighting was animated rather well, there were some times when I thought it seemed a touch out of character. Dodging bullets? Backflipping? I'm sorry, but it seems to me like he'd blast his way through enemies without all of those fancy-shmancy stunts. After all, the Chief is more Rambo than Neo.
Aside from that, run the dialogue through a spell checker, tone down the music just a touch, and try just a little more logic. After all, even a parody has to have a grain of sense.