Crossfire should install and run on any BSD variant that supports X and has the libraries which Crossfire requires.
The easiest way to install Crossfire on FreeBSD is to use the ports tree. The version there may lag somewhat behind the latest release, but it will be tested for FreeBSD and automatically install any needed dependencies. (To stay current with the latest development version, see the Crossfire SVN page.)
If you have the portupgrade package installed, install the server and/or the client as root:
portinstall games/crossfire-server portinstall games/crossfire-client
Without portupgrade, install the ports manually:
cd /usr/ports/games/crossfire-server && make install cd /usr/ports/games/crossfire-client && make install
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