Bungie has released a video walkthrough of an entire single-player mission in Halo Reach.
So-called Bungie "audio gurus" provide developer commentary as the blast their way through the chaotic mission, entitled 'Tip of the Spear', which we played and previewed for you in detail right here.
This is must see stuff. Unless of course, you're like this editor and want to go into the game completely clean. It's out next week people, not long to wait now.