When it comes to longevity of gameplay and long-term monetization of customers, how viable are  single-player gaming experiences like this one going to be in the long term?

EJ: I think there is an interesting question in how many projects should be offline products and how long that is going to be viable. Half-Life 1 was a really offline product. I think customers want to find ways to talk about the thing that they are a big fan of with other people, and ideally experience it the same way.

That doesn't mean every game needs to be multiplayer. With single player games that were completely in a box, and there was no way to experience anything else, I think there are things that customers want that those games don't take advantage of.

That could just mean that you want to be able to chat with other people who are playing through the same part of the game as you, or the fans can write commentary nodes in the game and everyone can experience those to take advantage of the fact that there is a huge community of people that want to interact with each other.

I still think the analysis that every product needs to be a competitor in multiplayer, or an MMO, is incorrect; there are a lot of people who want an experience without the stress, so I don't see that changing.

It's interesting to think about  -- numbers suggest that the popularity of guided single-player experiences is dwindling. That may mean that the highest-quality studios will no longer be able to invest in the development of those titles, and thus that type of experience won't improve.

EJ: Part of it is thinking through he reasons for making decisions. You brought up piracy being a reason to not do single player, which I think is a pretty crazy analysis on an issue like that; that's making a decision for your customers about the types of products you are going to build without, by definition, including your customers in that at all.

You're saying that because of these pirates, you get no single player experiences, which makes no sense to me. If there are as much players that want single player experiences, you should go build that. I think there are plenty of people that still want to have single player experiences. Look at Mario; those games do really well.

True, but I feel like those experiences, for adults, are already rare, and will continue to become more rare because it's difficult. Can studios like yours survive without making people essentially pay to level up?

EJ: One thing to think about is, when we are building a game like Half-Life 2 or Portal, monetization is a separate thing that, in the context of the game design, doesn't make a huge amount of sense, really.

We are trying to exploit the psychology of the people that play our games all the time. We are trying to change their emotional state, and trying to predict what their emotional state will be based on what we are doing in the game world.

What's compelling for people, like, "Hey, they're getting a huge reward here, they are going to be happy. They are going to be challenged on the skills that we taught them here and that's going to be rewarding them." There is a non-customer-hostile way to think about what we are doing. There are hostile ways too, though. (laughs)