Left 4 Dead

Well, there are 20 maps that are laid out across four campaigns: two urban and two rural ones. You played one of the urban ones, the hospital, which we began with tonight, and the farmhouse one is the first rural one, and the other two we may or may not show off before release, but they'll be similar in scope. The environments create a little bit of a different mood and variations in gameplay.

If you're a solid team and you're successful all the way through the mission, it should take you about an hour and a half. So, if you're blazing through it, and everybody's well oiled and whatnot, it's probably about six or seven hours of play. But, you know, the AI director that runs things is intentionally built to create a dynamic experience to how successful you guys are doing.

Whenever you enter a room, it'll be different to the last time you entered it. The idea isn't playtime in the sense of a single-player game; it's more trying to be a Counter-Strike thing, where every time you play Dust it's a little bit different. We're using dynamic AI to populate it with more than just the other team.

We're going to pour it on you, yeah, for sure. The AI director is very in touch. It's reading many things, like your movement and your accuracy. If the team is functioning well as a unit and ploughing through the game, it's going to rain on your head and try and slow you down. If you guys are stumbling a bit and struggling, it'll back off a bit. It's also trying to do that throughout the experience regardless of whether the team's really good, or the team's really bad, because we found a lot in Half-Life 1 and more so in Half-Life 2 that there's a notion of pacing that needs to be applied to games. If you're constantly barraging gamers, they're going to get battle fatigue, and they're just going to be overloaded. The dynamic moments of the really low lows, mixed with the really high highs creates some of the tension which hopefully we're giving you with Left 4 Dead.

There's presets to sort out where you start off, and then there's the equivalent of a volume control inside each one of those. Even at Valve, on the insane level only the best people finish one out of three times.

Most, I think. We're not really doing a lot of them. We just see the weapons as a vehicle for the gameplay, and all the weapons are very much real-world, modern day s*** that you would find lying around if panic broke out in London or Seattle. So there's not a lot of 'and then you get the big science fiction gun - the Portal gun or the gravity gun'. Everything's shotgun, pistol, Molotov. The scope of the game, and the things that we're trying to be more creative about are things like being able to help your team-mate off a ledge, share the med-packs, force people to stick torgether, and being unapologetic about how unforgiving we are if you don't stick together.

Those are some of the ingredients we think made Counter-Strike great. When I first went into a meeting with Sierra and said we should turn this mod into a retail product, they pointed out that there's no-single player, and if you get taken out you have to wait as much as four and a half minutes to get back in if it's goes to the full five minute clock. 'There's no way this game will sell. It's just too unforgiving.' And finally we convinced them to put it out, to try it and see what would happen, and it turned into a hit. We think that those natures of...there was no single-player, it was a multiplayer game, it was for people who wanted to play multiplayer games; that was it. We didn't waste time trying to develop the single-player game first, and folks responded to that. They said we want a game where there's consequences, like if I don't stick with my team, if I don't watch my ass, I'm going to watch the other guys finish the round. In a similar fashion we're being completely unapologetic about not working as a team. I think we're seeing folks care more about their team and care more about taking care of themselves.

You know, I see all of the characters as just skins. You define it as the weapons you pick and the way you play. It's not like Team Fortress where the character that you choose defines the role.

On the Infected side, it's completely different, and I like playing the Boomer, because all you have to do is find [survivors] in a tight space and rush them, and they can't help themselves but shoot you. And you're a grenade, and they don't want you to vomit on them and summon the zombies, so they're going to take a chance and hope that they're far enough away. The Boomer's the flamboyant one of the Boss Infected. The Tank is similar, but there's just something more hysterical as playing as the Boomer that I enjoy.

On the Infected side, yeah. Again, that's part of the unapologetic nature of it. We know there's a lot of work left to be done on the Infected side. The reason, a big reason why the game hasn't shipped yet is we haven't made it accessible enough, but even when we're done, when we do get it to where we want it to be, it's going to be the harder class to play as, there's no question about it. We want folks to play survivor, learn the game and then graduate on to play infected, just as in TF2, you start off as an Engineer, or a Heavy Weapons guy or a Medic, and then you graduate to Pyro, and then you graduate eventually to Spy. So, that makes the game have legs and be more interesting than 'I've played it this week and I'm done with it'.

Up in the air. It's not going to happen at the same time as the other two clearly, because it's not in development yet.

Well, right now it's just not being done. But it were to be done, it'd be done by a third party. Valve's PC, and we just got our 360 team together, and we're really proud that we got Orange Box out at the same time [on 360], and I think we did a really good job of making the products comparable, so it was just a matter of which system you preferred to play it on. Do you like keyboard and mouse, or do you like the gamepad? Do you like the couch, or do you like the den? If folks want to do a PS3 version, we're open to talk with third parties about that.