Web site: crossfire.real-time.com
Platform: Linux, OS X, Windows, Solaris
License: GNU GPL
First release: 1992
Crossfire – a free, open-source, cooperative multi-player RPG and adventure game. Since its initial release, Crossfire has grown to encompass over 150 monsters, 3000 areas to explore, an elaborate magic system, 13 races, 15 character classes, and many powerful artifacts scattered far and wide. Set in a fantastical medieval world, it blends the style of Gauntlet, NetHack, Moria, and Angband.
To play the game you’ll need to have access to a local or remote server.
Crossfire is freely distributed under the GNU license and the code may be obtained from a number of FTP sites. Take note: you will need at least an ANSI C compiler (i.e. gcc) and UNIX to build the game.