There's still a huge market for single player-only games, developer Valve has insisted.
Answering an assertion from Gamasutra that single player games were doomed as they're harder for publishers to monetise and easier to pirate, Portal 2 project manager Erik Johnson said, "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."
"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," he continued.
"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."
Johnson added that, as a designer, he tries to keep financial concerns outside of what he and his team are trying to achieve.
"One thing to think about is, when we are building a game like Half-Life 2 or Portal, monetisation is a separate thing that, in the context of the game design, doesn't make a huge amount of sense, really.
Portal 2 is due for release on PC, PlayStation 3 and Xbox 360 next year.