Eurogamer Said: Valve has said it will definitely be making more Portal, confirming plans to add significantly more than just "a bunch of new puzzles".
Speaking to Eurogamer, spokesperson Doug Lombardi said it was less a matter of if and more a matter of what and when.
"There'll be more Portal, for sure. But the details of that, to be honest, we're still working out," he said.
"The only smart thing we did for Portal was to hire those seven kids and give them the support they needed to make the game."
Unsurprisingly Valve is reluctant to be rushed by a release schedule. It's adopting the same policy for Half-Life 2 finale Episode Three.
"Gordon is our number one guy," said Lombardi. "In Episode One I think we left people with some big questions. After Episode Two people saw it was going somewhere.
"With Episode Three we want to live up to the promise of where we are taking things to; there's a lot of work being done to make sure we deliver on that promise."
He added, "Exact details on what's next for Gordon are a way off; probably months not weeks."