Obviously the network requirements of Halo are... I don't want to impugn anyone else, but they're probably the most robust of a shipped shooter, and the complexity of what you can do with recording matches and having people in and out. 

MZ: I understand it's pretty sophisticated.

And that has to affect things in a way, too, with performance issues.

MZ: Performance, absolutely. As far as our actual networking, on the environment art side, it doesn't impact us that much. There's certain things for split-screen that we have to think of, and we test thoroughly obviously over Live connections and system link and all that.

BJ: In regards to safe zones, though, one of the things that you guys used to joke a lot about was... giving the player the ability to go anywhere they can in the world at any moment in time. All of the old tricks of the trade kind of used smoke and mirrors. You guys can't hide anything.

MZ: That's very true. Well, no, there is somewhere to hide. It's beyond the soft ceiling.

BJ: It's like the inside of the Pelican is now fully rendered, and you can fly inside if you want to, even though as a player you'll never go there.

MZ: In a way, we were initially kind of dreading that. Like, "Oh man, you're going to be able to peek at all of our laziness." But actually at the end of the day, I think it was kind of good, because it actually more often than not... the screenshots I saw where I would be afraid of exposing a bad angle... users were actually coming up with better viewing angles than we did.

A lot of times, they're actually getting to see stuff that we had to model for that one percent edge case, where somebody could grenade-jump up. We were like, "Okay, I have to model that and texture that, but I know no one's going to see it." But now, tons of users see it, because they're flying the monitor up there, and that was awesome.

We didn't necessarily author a lot more content than we did on Halo -- well, we did more than Halo 2, but for different reasons -- than we otherwise would, if we didn't have safe zones. In some ways, it's actually kind of satisfying, that some work paid off that you didn't think would.

I remember when the beta came out, and somebody clipped through Master Chief's helmet somehow, and found the face texture. Those are the things that must be hard to anticipate.

MZ: Basically our golden rule of making something bulletproof is that it will never be bulletproof. The players will always find a way to break your game, especially when you expand to the player population that we have. We have an amazing test team, but there's no way they can compete with several million users, you know? It's just impossible. There's a lot of smaller games that get away with a lot more because of that.

At the same time, having millions of people play your game is the reward as well.

MZ: Oh, absolutely. I'm not complaining.

Yes you are! I have it on record.

MZ: (laughter)

BJ: There's a whole population that thrives just on breaking Halo, and doing stuff in Halo 1 kind of built this hardcore following, because these guys are trying to break the physics by launching Warthogs in the air and doing these things that would never happen intentionally. In Halo 2, I think a lot of that went away, and in Halo 3, people feel free to explore and be more strident and do things they couldn't do before.

MZ: I think you could argue that it's that sort of adventurous spirit of the user base that has inspired things like Forge. We want to empower that as well, because it's way more exciting.