Valve's Chet Faliszek

In the very beginning we had this thought that randomisation would be the greatest thing ever, and we found out it wasn't. It had this really negative effect, and I think if you look at something like Counter-Strike and de_dust, where you want to test yourself against things you know, when something bad happens you know if you get five more feet you can get in this doorway. The sections we've done give you some of the randomisation and then around it there's things you can count on.

For example, the crypts are really random and you have to figure out which way to go. We don't do a lot of pathing where you hit dead ends, because dead ends suck in mazes, but at the same time you're trying to anticipate which way and there'll be some different routing you can do. So we give you some landmarks you can use, like there's a spiral and a gate, so you can use those. Absolutely random wasn't what we thought. Playtesting with outside people as well as internally, we were finding ourselves exhausted, or, 'I was never really planning, just reacting,' and at that point you're making one of those games where you hit the mouse as fast as you can like Wac-A-Mole or something. We wanted to balance that.

Have you played Versus online against good peope? They'll form this really tight ball that's really hard for the Smoker or the Hunter to work inside of, because they're just not straying far enough. If you think about it, the Hunter's built a lot of times to get the guy who's running, and the Smoker's to get the straggler. What the Charger does is he comes in and he's pretty much... unless you get him right away, it's going to hit, and he's going to grab somebody, and he'll stumble everybody else. So if you're too tight in a group, you have this negative where everyone's going to get stumbled and one guy's going to get taken off and be in trouble.

So if you just spread out a little bit more you can avoid him. But obviously by spreading out a little bit more the Hunters are a little bit more effective, and so are the Smokers. It's like in basketball. You know the three-point line? Essentially you get bigger points if you shoot further out, but what that meant was people were shooting further out, so people who would normally be inside, on defence, had to move further out to defend that guy. At the same time, dunking the ball became really popular, because all of a sudden these guys spread out to cover those guys, you had open lanes and you could go in and slam-dunk. So the side effect of giving the three-point play was to open up slam-dunking more. The same thing happens with the Charger - you have this one thing built to take care of this, but the side effect is it makes the other infected better as well.

As I was saying, doing one [special infected] at a time isn't enough. Like, the Spitter, if you spit between one guy and the rest of them, and then someone pounces that guy, they can't just run over and bash him off because of the spit in between. They've got to wait a minute for the spit to die down, or shoot through the spit. Same thing with the Jockey. He grabs that last guy and takes him off. Especially with what we call 'returns'. Say if you play where the gas station is [in No Mercy], you've got to go up the elevator and run around, and if you get pulled off you've got to do it all again - we call that a return. A Jockey is often great at sending someone down a return, where you're almost safe and then you've got to do this big route back again.

We have played around with that, and it's just... it gets very complicated for people to understand. I think there's another thing - when you swing the axe, it's super-powerful and you're killing a bunch of people, and we want to make sure they've got this little point where they're vulnerable and they still get attacked. And, really, the axe is pretty heavy, the cricket bat... If you're walking around with baseball bats in both hands you're a man, you're a tough guy.

[Makes wounded face] But he had the HEV suit though...

It's got a lot of pockets.