In the words of its original author Frank Tore Johansen:
"Crossfire is a multi-player graphical arcade and adventure game made for the X Windows systems environment. It has certain flavours from other games, especially gauntlet and the rogue-like games (Nethack, Moria, Angband, and Ragnarok.) Any number of players can move around in their own window, finding and using items and battling monsters. They can choose to cooperate or compete in the same world.''
In the years of development that have followed, Crossfire has grown to encompass over 150 monsters, ~3000 maps to explore, an elaborate magic system, over 15 character types, a system of skills, and many, many artifacts and treasures.
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.
Read more about the start of Crossfire, as posted to the Mailing List. (Sep 2, 1999)
Here is what some other sites have to say:
Building With Someone Else's Blocks: Going Open Source With Games - http://www.gamasutra.com/view/feature/6467/building_with_someone_elses_.php
Website for the Metalforge Server
Crossfire at Netarbeiter
Kevin's Crossfire Project Development Page
Crossfire Map Atlas
Crossfire at Open HUB
"Crossfire is a multiplayer graphical arcade and adventure game. Several
players (over the Internet) explore the maps, enter various houses and
dungeons, find and use items and fight monsters. This game works in
the X Window environment. Depending on your machine, you can have color
or monochrome graphics, sound effects, etc."
In the October Issue of Linux Journal, there is a review of Crossfire.
"Crossfire is a different kind of game from the rest of
these dungeon crawlers. The Linux Game Tome describes it as a cross between NetHack and Gauntlet, and that's actually
fairly accurate. The game is graphical, multi-player (!) and immense.
With over 150 different monsters, about 3000 maps, 19 character classes,
about 65 different weapons, dozens of armours, helmets, shields and
clothings, and 18 levels of magic available to wizards (with roughly
85 spells at last count), Crossfire is a whole different world in which
you and your friends can live. Any number of people can have clients
(even available for Java and Win32), but the server has to run on a
UNIX-based system such as Linux. If you're tired of being an @ and want
to be an animated graphic again, here's where you can do it!"
Wikipedia - http://en.wikipedia.org/wiki/Crossfire_game