It's been a while since I've thought about Portal 2, but the time is right. Portal Stories: Mel is out now on Steam, free to anyone who owns the core game. This is a standalone mod with its own voiced storyline, soundtrack, and custom assets. A new four-hour-plus Portal adventure, basically.
"In the early years of Aperture Science Innovators, Cave Johnson's scientists rushed to get everything working to catch up with the growth of the company. Unfortunately, not everything worked as it should. Mel took part in a faulty experiment, the Aperture Science Innovators Short-Term Relaxation Vault, falling asleep for years. Now, with a fake Cave Johnson telling her she needs to escape the facility, and a new device, the mysterious Aperture Science Innovators Handheld Portal Device Prototype, her mind races with questions."
And I'm hooked. I particularly like the team's design philosophy: "The difficulty is always in the logic, never the execution. Portal Stories will never require any ninja skills." High hopes for this one.