On the tech front, Lehto confirmed that the game engine has "been entirely re-written" in order to facilitate what Bungie wants to do in Reach. Specifically, its goal is to make the world more expansive, put a lot more on-screen and introduce much more detailed character, environment and weapon models. Addressing the former, Bungie showed a test animation of a battle between Noble Squad, eight marines and 30 Covenant -- it was even more impressive looking than it sounds. We got zoomed-in looks at things like rifle scopes, which are detailed down to small writing and screws.

The game is pushing about four million polygons more than Halo 3 overall, we're told, with a completely re-written animation system and A.I. The result, Bungie hopes, will be a much more realistic world to look at and be involved with. From the stills and footage we saw, it's on track to deliver -- the game looks phenomenal. It promises to sound great, too, as every sound effect has been re-recorded.

Lehto told us the revamped game engine and A.I. will allow Reach to adopt a more "sandbox" style within its levels. They're going to be much less linear, he said, and much less scripted. This will, Bungie hopes, give players more freedom to approach combat in their own way. One thing we saw along these lines: Special kills, which cause the camera to pull out to a third-person perspective in order to show off their intricate animations.

We were shown a live demo of one of the maps being included in the upcoming Reach beta. The cliff-top locale certainly was expansive, with a mix of indoor and outdoor areas. This area will evidently serve duel purposes as a campaign setting and multiplayer map. While Jarrard ran through it, we got a good look at the revamped battle rifle and a new Covenant weapon, the Needle Rifle, which allows players to combine ammo for a single, much more explosive shot. It was also revealed that health packs are back, and that equipment you pick up during the single-player campaign (the example shown was an enhanced sprint ability) won't be single-use -- you'll keep it from there on out.

According to Bungie, Halo: Reach is currently in alpha. What it showed today definitely got us excited about the much larger, more detailed world and overall heightened realism. And, we'll say it again, the game looks amazing in motion. Now we just need to get our hands on it. E3, anyone?

Bungie's definitely using Reach to explore some of the unknown background of the Spartans, but they're also using the game as an opportunity to reintroduce the Covenant, starting with the Elites. Bungie wants to make them feel as though they truly are formidable opponents seemingly to the extent that you would feel some kind of dread whenever they appear on screen. Other enemy types are being upgraded, but there will also be a group of enemies that didn't appear in other Halo games because they were made extinct through the battles on Reach.

Lehto then went into greater detail about things the team is doing on a technical level to achieve the epic scale that they're aiming for, and it sounds like they've done quite a bit. Just about every facet of the Halo engine has been torn down and rebuilt to accommodate everything from more detail in the character models and environments to better animation and sound. In terms character model improvements, we actually got to see a visual representation of the progression with an image that showed a version of a marine from the original Halo through Halo: Reach, and the level of added detail in the Reach version of the marine is pretty astounding. Another impressive aspect of Halo: Reach--at least on a visual level--is just how massive the environments are. We got a brief glimpse of a few of them (and a closer look at a multiplayer map) and the view distance is pretty astounding.

Of course, part of the reason why these environments are so much larger is because Bungie is aiming for an epic scale for the battles. At one point in the video documentary we were shown (which will be released on Xbox Live tomorrow), one of the members of Bungie says that with the new engine, a battle can theoretically accommodate four Spartans, eight marines, and 30 Covenant enemies. At the same time, Bungie wants to reinforce that these battles and indeed the entire game are designed to be a sandbox, meaning that there won't be a whole lot of scripted events. The development team wants you to feel like you can approach a situation in any number of different ways and experience the results based on the approach that you take.

When the video documentary ended, we jumped into a real-time demonstration of a multiplayer map called Power House, which will be a part of the Halo: Reach beta when it launches on May 3 (and it will be available to those who own Halo 3: ODST) . Lehto explained that all of the multiplayer maps are taken directly from the single-player campaign, but in the case of Power House, the multiplayer version takes place during the daytime whereas the singleplayer incarnation is a nighttime affair. The first thing that comes to mind when viewing this map is just how massive this desert canyon-like setting is, but there are also appear to be plenty of close-quarter areas with the power plant area of the map.

We then move to a super close-up of a single Spartan standing in the environment, and we mean super-close-up--we could even see the fine lettering on the stock of the Spartan's rifle. It's here that we also get a demonstration of how the sound has been overhauled. The Spartan squeezes off a few rounds from the new rifle (explained as a revision of the typical Halo battle rifle that has medium to long range) and immediately we hear thunderous gunfire followed by booming explosions of grenades. All of these adjustments in sound are meant to make the weapons in Halo: Reach have more impact and feel much more powerful than they did before. We then get a quick glimpse of the needle rifle, which simply looks like a much more beefed up version of the standard needler. A few other details we learn during this audio demonstration is that health packs will be back and used as incentive to get people exploring more of the environment.

But the biggest detail about multiplayer is that in Halo: Reach you can actually hold onto equipment that you find and use it repeatedly whereas in Halo 3, you could use it only once and be done with it. This is demonstrated to us with the sprint upgrade, which allows you to run for a finite amount of time. If you exhaust the meter shown at the bottom left of the screen, then you need to wait for it to recharge before you can start sprinting again. There will be a cross-section of upgrades available when the beta goes live so people will be able to get to try them out and give their feedback to Bungie. The Reach beta will also include a few different maps as well as a few different match types, but Bungie wouldn't go into specifics about what will be there. But the team does view the beta as an opportunity for Halo's biggest fans to jump in and essentially tear it apart to find things that they like or don't like about what Bungie is doing.

Overall, the amount of work Bungie's putting into Reach seems to fall in line with what they call, "the definitive Halo game." While the impressive changes to the visuals and sound are already immediately apparent, we'll be interested to see how that has trickled down to other aspects of the game, like the AI. We'll be sure to have much more coverage of Halo: Reach as the beta approaches and before the game's release later this year.

To do this, Bungie had to "take a generational leap forward" with animations and artificial intelligence. I saw just a bit of it in motion and can confirm that the textures, animations, lighting, and character modeling is leaps and bounds above Halo 3. Bungie has over 30 guys working on the engine and it shows. As for AI, we'll have to wait and see though the possibilities sure do sound intriguing.

Download it, youre missing some cool stuff.