Harry has posted a spoiler of humungous proportions, laying out the entire story of the game in summary form.

If you don't want to know, don't click the link.

HBO's own Louis Wu posted a note that IGN has put up a complete-- and I do mean COMPLETE-- walkthrough of Halo. As Louis notes, you can get around having to register with IGN to see it if you turn off javascript in your browser. Here's what they say in the introduction:

Halo is the best first person shooter ever made. It's not the first, it's not the most influential, it's simply the best. The combination of great control, amazing story, excellent enemy AI and slick level design adds up to a truly impressive game indeed. Is it the best launch game ever for a system? It would be hard to argue with Super Mario Bros. in this category, but Halo will have you rethinking this. It will have you rethinking a lot of things. Like which console you're going to buy this holiday season. Like whether or not you need to eat. Or sleep. Or do anything you should be doing. The single player game is a masterpiece, and the multi-player will keep you and fifteen of your closest friends warm for years to come.

If you don't want to know too much about the game before you play, don't read any further than that.

UPDATE: Harry pointed out that the walkthrough is detailed, but not complete; it only covers the first three missions or so.

With the Xbox's launch and Halo's release now upon us, we know there'll be some sharp divisions on the site, especially between those who will be playing Halo on an Xbox these coming weeks, those who won't be able to get their hands on one for awhile, and those who are waiting for the PC and Macintosh versions.

To that end, we've added a special spoiler forum to the site. The recent posts on this forum will NOT be displayed on the front page (so as not to tempt those trying to wait, or inadvertently display a spoiler in a subject line).

Marty O'Donnell is telling everybody over at the halo.bungie.org forum they should think carefully before deciding to watch the Gamespot movies recently made available. While it may be too late for a lot of us, he's still got a good point:

Here's the deal. If you are someone who's not sure whether or not you want to play Halo or buy an Xbox or whatever, then please go check out the movies and see if it helps you decide. If however, you are already a fan of Halo or Bungie and are planning on purchasing and enjoying Halo to it's fullest extent, then please ignore Gamespot and all the posts dealing with these movies.

The upshot is that while the movies might not give away new plot points, seeing so much of the game's introductory cutscene (which is to say, ALL of it) plus the rest of the first level might spoil the dramatic tension when you first slip Halo into the Xbox already knowing what you're going to see. Thanks halo.bungie.org.

Okay, true believers... before you click the link to read GameSpot UK's preview of a nearly complete copy of Halo, decide how much you really want to know before you play the game for yourself. While the revelations aren't completely new or startling, some people probably don't want to know any more about the backstory than they already do... so if you're in that part of the pack, you've been forewarned.

The following excerpt has been rated NS for being a Non-Spoiler. It does, however, expose a bit about how cooperative play is going to be handled:

Aside from the single-player campaign, Halo features a variety of multiplayer options. The entire single-player game can be played cooperatively by two players. This mode handles death in an interesting way. If one player dies, the remaining player can either retreat or finish the current battle, and the dead player will respawn. If both players die, however, they return to the last checkpoint and have to try again.

Only two players? Hmm... here's hoping that's a minor inaccuracy someone will soon correct for us. I'd hope that with multiple Xboxen networked together, you'd at least be able to play cooperatively with as many players as games like Marathon allowed us to half a decade ago.