When fans of a game franchise hear about a sequel, their reaction is rarely as divisive as those of Left 4 Dead, who responded to the announcement of Left 4 Dead 2 with either joy at the possibility of keeping zombie hordes at bay using axes, and those who felt betrayed that Valve were abandoning their previous favorite so quickly. Prima games got hold of Doug Lombardi to hear about his reaction to the fan response, a stronger story line, and how “a big wild arm” will keep people from hiding in corners.

Prima: Left 4 Dead 2 seems to have progressed at a distinctly un-Valveish pace. Why is that?

Doug Lombardi: It really depends on the kind of game you're trying to build. When you're making a Half-Life 2 sort of game, you're hand-stitching every moment of the gameplay: the scripted sequences, the dialogue, the close-ups. With a multiplayer game, there's different criteria: weapons, sounds, levels and things like that, but you don't have a lot of this really arduous hand-stitching that you have to go through on single-player. The other thing is that on Left 4 Dead, we have the AI director, which allows us to get stuff up and running really quickly. Then there's just the amount of people you have working on it, and the number of good ideas that are just slam-dunks. The Left 4 Dead 2 team is 30 to 50 percent bigger than the first team was at its largest point, and they had a lot of ideas coming off the first game that were just slam-dunks. There wasn't a lot of testing involved in, "Shall we put a frying pan in?" Yes! We don't need to test that.

Prima: What happens from a development perspective between realizing you have more Left 4 Dead ideas to deciding to put out a full sequel?

Doug Lombardi: It's completely inside-out. We're privately held, we've been very fortunate in the sales of our games, so we have absolute flexibility on what we want to do and when we want to ship it. Everything starts off with a whiteboard exercise, where we get all of our ideas up on the wall, and then we try to figure out how to get that into customers' hands. In Left 4 Dead's case, there was a bunch of stuff we wanted to do: get the other versus campaign modes out - some people were tinkering with survivor mode, that kind of stuff, and that just made a load of sense for DLC. But then there was other stuff: we want to change the way finales work, we want melee weapons, we want to do more with the story. Okay, that side of the whiteboard is feeling like a different game. That's really the process it went through, and then timing is just looking at all the things you want to do, and then you make your best guess on scheduling.

Prima: So at the moment, you have separate teams working on Left 4 Dead 2 and supporting the original game?

Doug Lombardi: There's a couple of different teams, actually. There's guys working on Left 4 Dead 2, guys working on Left 4 Dead 1 stuff, and then guys working on the authoring tools for Left 4 Dead - the mod-making stuff. Regarding the Left 4 Dead 1 content, we'll be announcing stuff in the coming weeks, but there's nothing I can say about it today.

Prima: Did you expect the negative reaction from some fans following the announcement of Left 4 Dead 2?

Doug Lombardi: We obviously listen to the community a lot. That's one of our staples. Did we anticipate it? No, we didn't, but I think that one of the key things is: announcing Left 4 Dead 2 doesn't mean we're abandoning Left 4 Dead 1. Another thing is it's important to remember that E3 is where you go to announce new titles, specifically titles that are coming to retail. We do press there, but it's not really a venue for announcing DLC or mod tools. So I think there was a little bit of confusion that we created unintentionally, by announcing a sequel and not having the complete story ready: announcing it and not saying, there's still a lot of stuff being worked on for Left 4 Dead 1, and the mod tools will work with both games. I think that, over time, folks will see what we're up to, and there's more of this story to be told in terms of what's to come for both games.

Prima: Left 4 Dead 2 is going to have an increased focus on story, an element that was trimmed in the first game following play-testing. Is there a danger with a game like Left 4 Dead, where so much of the fun comes from players' own anecdotes of escape and last-minute disaster at the hands of the AI director, that the story you're trying to tell gets in the way of the players' personal stories?

Doug Lombardi: Yeah, and we have to be careful not to go too far with this property. We saw a number of reasons to pull back with the first game, primarily because the replayability suffers with a scripted sequence: if you come back and you have this procedurally-generated campaign in terms of the enemies and weapons, and then every time you go through it there's a long bit of scripted story at the beginning of the third level, that screws up the suspension of disbelief that it's different each time you play it. It's gotta come out. Then, more specifically, we had much more dialogue amongst the characters originally, and that was really getting in the way of people understanding the co-op nature. We saw something similar when we were playtesting Portal: in the first iteration it was much more lush in terms of graphics, and there was just a bunch more crap in the levels, whether it was furniture or whatever, and people were having trouble identifying the pathways they had to go through to solve the levels. We had to make it this sparse environment to get to the gameplay.

Now, with Left 4 Dead 2, we've learnt that the big scripted sequence in the middle of the campaign really breaks stuff, so we're not going to do that. We're definitely by no means trying to make this a Half-Life 2-style game with heavy dialogue and story stuff. But what we do think we can do is, out of the game and the movies, bring more story to the game in terms of the players' dialogue. Then there's little tricks we did in Half-Life and Portal: televisions and radios and writing on the wall is a great way for people who want that story to get it, but for people who just want replayable co-op, they can just blow through.

Prima: Even with Left 4 Dead's AI director, after a while, players spot techniques that they can exploit again and again - things like getting into a corner to keep the horde at bay, for example. How do you ensure things stay fresh?

Doug Lombardi: That's one of the reasons we went for a sequel. We realized people were kind of gaming the game, particularly with that backing-up-against-the-wall stuff. So for one thing, we're redesigning the finales, and turning them into scenarios where we put you on the run: you have to keep moving, or you'll get overloaded. Then there's new bosses like the Charger - that big wild arm, that's to bat you around and move you about. You can pretty much be guaranteed that if you wedge yourself up against a wall, you're going to see a Charger pretty quickly, and he's going to swat you away.

There's always going to be a level where, when people get 100 hours in, they're going to discover a way to game the game. That's fine. And then we'll figure out how to counter it again, and give them something else to figure out how to break.

Prima: Did you ever discuss using the AI director to move actual geometry around, or is that something that's just never going to be a good idea?

Doug Lombardi: It's something we're toying with. In New Orleans, the coffins are above ground, so you have these mini mausoleum buildings, for example: the first time you go through, the mausoleum will be laid out in a certain way, and the next time it will be different. It's not quite random level generation, but it is doing things with world objects and pathing to give you one more thing to keep you on your toes. Another thing is weather effects. When you're in the swamp for example, you're up to your waist a lot of the time, and one thing we might do is roll in fog effects, so you've got enemies coming at you from ten feet of visibility. Obviously, only if you're doing well will you see that, but it's another way to tailor to people's skill set.

Prima: Is there a point at which Left 4 Dead and Half-Life 2-style design ideas will start to converge? Is there an opportunity for procedural single-player games that still have really dramatic scripted sequences?

Doug Lombardi: The AI director - I don't want to say it fell out of Half-Life 2, but it was definitely a jumping-off point of stuff we did in Half-Life 2, particularly Episode 2. There are a couple of key battles where the number of Combine, and where they come at you from, uses something like that. It's much cruder than what we accomplished with Left 4 Dead, but there was some of that there. I think you can definitely extend that. You're still going to have that moment where you need those big Half-Life and Modern Warfare set-pieces where there's got to be some hand-stitching: by nature, that's going to be the same each time you play it. So it's weird: you're mixing replayable sandboxes with these climax moments which aren't going to have that - at least for the foreseeable future. I don't know to what extent that's enjoyed by the consumer. I don't know how many times people would be willing to play the single-player part of the experience.

My hunch is that, in the case of Half-Life, or Half-Life 2, or Modern Warfare, there's a chance that a higher proportion of people finish those games because the combat didn't feel like a shooting gallery and the climax were really satisfying. But my hunch is that people finish those games, and then they don't say: "Wow, that was so good, I want to play it again." I haven't spoken to people who have said, "I wanted to play Half-Life 2 ten times." Instead, they want to find out who the G-Man is.

Prima: On that subject, as Half-Life 2: Episode 3 will presumably bring large parts of the narrative to a close, are you wary of explaining too much? Do people need to have some kind of mystery left to ponder on?

Doug Lombardi: Yes, I think part of the fun is definitely the secret part of it, letting the community find stuff and theorize. There have definitely been people guessing what was going to happen, say, before the episodic games come out. It's funny because a couple of people are really on the money, a couple of people are just totally out there. It's fun for us to watch that, and, of course, it encourages us to be more misleading and mysterious about stuff.

Prima: Have you been working throughout Half-Life 2 with a strong sense of the ending, or has the approach been more flexible?

Doug Lombardi: There's a little bit of both aspects. You have to have basic direction, and basic groundwork: Freeman's relationship to the G-Man and that sort of stuff. But things like the decision to axe [a major character] at the end of Episode 2, that wasn't planned when we were making Episode 1. You have to allow yourself that freedom, both in terms of story and the basic gameplay. I mean, Ravenholm was at the end of Half-Life 2, and then we were playtesting with outside people and they were saying, "Wow, this gravity gun's the best thing in the whole game!" so we were like, "Ahh, Ravenholm's the second chapter in the game now!" I don't think we planned to keep Alyx around or as prominent after Half-Life 2, but as soon as we showed it, people just gravitated towards her, so, okay, she's going to play a bigger part as we go on. You have to be able to respond to what people want. You want to see what the common themes are that resonate, and then turn up the volume.

Prima: On that subject, can you say anything about Half-Life 2: Episode 3 or Portal 2 yet?

Doug Lombardi: Nope! [Laughs.] I really can't say anything. We're always trying to do new stuff with every game we put out, but beyond that there's really nothing I can say.