Valve boss Gabe Newell has told PC Gamer the firm will likely release another quick sequel to one of its games - a la Left 4 Dead 2 - "at some point".
"I’m sure at some point we’re going to do it again," said the developer boss.
"The point is we learned something about that, which is… your point earlier was that we surprise our customers, and there’s a certain amount of entertainment value in that."
He added: "But then there’s also a certain amount of fear value in that, because the traditional surprise in the gaming industry is not 'Oh, I’m surprised: something good happened!'
"The traditional surprise is 'Oh, I’m surprised: X-Fire just got bought again and went away.' 'Oh, I’m surprised because something horrible has happened to a franchise that I’ve been following since I was a little kid.'"
Following the release of the original Left 4 Dead in 2008 for Xbox 360 and PC, Valve surprised everyone at E3 last year by announcing L4D2 in Microsoft's press conference for a release last November, barely eight months since L4D1 launched.
Portal 3 late next year, then?