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.
While I think Portal is seriously , I'd wouldn't hold my breath waiting for it.. i'm sure it'll be along in 2012 or something