Here is an interesting comparison of Cortana over the course of the 4 halo games:
PTesh adds his dulcet prepubescent tones over the top of one of the new trailers for weapons...
Try upgrading your browser to Google chrome (you wont regret it). There is probably an IE...
Level: The Package
The video honestly explains this much better than words can. You basically have to flip a switch and fight a bunch of Elite generals. Once you have done that, you unlock a door that upon entering will transport you into a corridor. Go down there and you will find a room basically full of easter eggs, a tribute to everything Bungie thinks is cool. HEE did not make it into the room unfortunately, maybe next time.