To play the game you need at least the uqm and uqm-content packages.
Those packages are included in the Debian archive.
You can optionally install the uqm-music package, which adds better quality
music, and the uqm-voice package, which adds full dialog support to the
game. Be warned that the uqm-voice package is over 100Mb! Since these
packages are large, and until Debian gets a 'data' section, they are
currently not available in the Debian archive. there is an apt repository at uqm.debian.net that has these
packages in it. It is maintained by the same person who maintains the uqm
packages in Debian. To use the apt repository, add this line to your
/etc/apt/sources.list:
deb http://uqm.debian.net/ unstable/
A mirror is also available thanks to Tollef Fog Heen (updated daily):
deb http://mirror.err.no/uqm/ unstable/
Replace the "unstable" with whatever version of Debian you are using, be it
"testing" or "stable" to get packages that match the uqm package in Debian.
Add the repository's key to your apt keyring:
wget -O - http://uqm.debian.net/key.gpg | sudo apt-key add -
Then run apt-get update, and you may apt-get install uqm-music and
uqm-voice.