XCOM: Enemy Unknown Released on Linux, Port Done by Feral Interactive

XCOM: Enemy Unknown, the tactical turn-based strategy developed by Firaxis, has been ported to Linux by Feral Interactive and is now available on Steam for Linux.
As it stands right now, there are two major companies that port games for Mac OS X – Feral Interactive and Aspyr Media. This platform is much closer to Linux than Windows, so it stands to reason that Firaxis wanted to have these companies make the ports.