Deep Silver and 4A Games today officially released a committed Mac version of Metro: Last Light via Steam, with an App Store release set to follow soon. A Linux version is also in development, scheduled for release later in the year.
Metro: Last Light on Steam will support Steam Play, meaning that owners of any Steam version will instantly find the game added to their PC, Mac and Linux Steam libraries.
Metro: Last Light for Mac and Linux will receive the same DLC packages as the PC and console versions. The Metro: Last Light Season Pass, and the Faction Pack and Tower Pack DLC will be available at launch for the Mac Steam release, and the upcoming Developer and Chronicles Packs will release on Mac alongside the PC and console releases.