Valve project manager Erik Johnson is convinced that every games does not need multiplayer and that using community features can create a connected experience in the absence of the multiplayer component.
Every game concept is not built for multiplayer. Tacking on a multiplayer element is a waste of time if the game was not meant to be in that realm. There are many gamers who love variety and immerse themselves in a single-player role-playing or strategy experience with as much passion as others, who dive into first person shooters and sports games. All games need not try to compete with other games multiplayer. There is more than one way to create a connected, shared gaming experience.
I still think the analysis that every product needs to be a competitor in multiplayer, or an MMO, is incorrect. If there are as [many] 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."
In 2011, Valve will be releasing Portal 2, the sequel to the wildly successful single-player puzzle platformer. It will feature a separate co-op campaign. Many are anxiously awaiting the next installment to test their skills, especially after seeing the co-op gameplay in action. Valve strives to provide a quality experience that will satisfy fans of the first game without being a mere copy of its predecessor.