America's Army 2.5 Assist can have add of Data files for playing
the Game. There is about 10 AddIns for This Games to could Get and 
use for playing and the Addins is for to get the main AddIn there
is for both Linux, Mac, Windows and WineMac.
The first Addin to use is the System Addin and then the Help addin.
 System
 Help
 Textures
 Maps
 Sounds
 Music
 Animations
 Movies
 Karmadata
 Briefings
 Staticmeches

The is there extra addin files like maps for ready to next version of version 3.0 or AA3.
Most of this game can be play om Linux, MAC and Windows as Client player, and the is a 
Server version too for both Linux, MAC and Windows.
http://aao25.com/