Portal’s ending theme may well be one of the greatest video game songs ever created, and the duo behind it are also working on the sequel’s music. Jonathan Coulton:

I live and die by the niche, basically. I write all these geeky songs. It’s Internet people who keep me afloat for the most part. But then, suddenly there was this Portal thing, and it was a global phenomenon, and it reached all sorts of people that I wouldn’t have otherwise reached.