May 19, 2010 – The second round of Steam for the Mac launch titles are available now. This week’s collection features a dozen games headlined by the first cross-platform multiplayer games offered via Steam.

This first set of titles that allow for PC vs. Mac cross-platform gaming include the co-op zombie hit Killing Floor, Altitude, and Madballs in Babo: Invasion.

‘We were thrilled when we learned that Steam was coming to the Mac platform and started working on a native Mac version of Killing Floor immediately,’ said John Gibson, President of Tripwire Interactive, creators of Killing Floor. ‘Steam’s advanced multiplayer support on both the PC and Mac has enabled us to bring Killing Floor to a whole new audience on the Mac and introduce them to the existing PC player community.’

To celebrate the launch of these titles, Killing Floor will be offered at 33% off its regular price (for a limited time). An Altitude Free Weekend promotion is available now on Steam, and those who wish to purchase the game and play beyond the weekend may pick it up at 50% off its regular price. And Madballs in Babo: Invasion is also available at 50% off its regular price.

More single player games are also available today including Sam and Max: The Devils Playhouse Episode 2, Hearts of Iron 3, and more. Click here to see all Mac titles new to Steam.

An additional collection of Mac titles will launch next week via Steam.

(View the rest of the article at Steam For Mac Launch Continues)