Portal 2 is in the works, this was revealed by Valve's Kim Swift on last night's episode of G4's X-Play. There have already been indications that more gameplay in the inter-dimensional puzzler is coming, but this is the first word that this will take the form of a full-blown sequel. The relevant quote comes at the 2:50 mark in the 3:05 clip: "Well, uh, I think… I believe Doug Lombardi, who is our lead marketing director at Valve, has announced Portal 2, so…" He hadn't actually, but that cat is now out of the bag.