Portal was the first Valve-developed game to be added to the OS X-compatible list of games available on the launch of the Steam client for Mac on May 12, 2010, supporting Steam Play, in which players that had bought the game either on a Macintosh or Windows computer could also play it on the alternate system.
1 Eurasian Pleistocene megafauna became extinct in roughly same time period despite having a much longer time to adapt to hunting pressure by humans. 2  However, the extinction of the Eurasian megafauna can be viewed as a result of a different process than that of the American megafauna.
Much of the Late Pleistocene age was dominated by glaciation (the Wisconsin glaciation in North America and corresponding glacial periods in Eurasia). Many megafauna became extinct over this age, a trend that continued into the Holocene. Also, human species other than modern humans died out during the Pleistocene.