Enemy Unknown, which launched on Windows PC, Xbox 360 and PlayStation 3 last October, was ported to Mac by Feral Interactive and released April 25. At the time, a representative for the company — which has also developed Mac ports of games such as Borderlands, BioShock and Deus Ex: Human Revolution — told Joystiq that it "doesn't release games on Steam." Yesterday, Enemy Unknown became the first Feral title on Valve's digital distribution service.
The game supports Steam Play, so buyers of the PC version also have a copy of the Mac port and vice versa. Cross-platform save game syncing is also available along with leaderboards and Steam achievements, and players of both versions can partake in multiplayer matches against each other. Either version costs $39.99 on Steam.