To install darkplaces just follow these instructions.
sudo apt-get install darkplaces
Which will install darkplaces and any other packages on which it depends.
|Maintainer||Debian Games Team <firstname.lastname@example.org>|
|Description||Game engine for Quake and similar 3D first person shooter games improved visual effects and lighting and many features for mods. It can be used to play various games based on the Quake engine, such as Xonotic, Nexuiz Classic, OpenQuartz, and Quake itself.|