[ Thanks to Chris7mas for this link.
]
“Xonotic uses the Darkplaces game engine, an engine which
started as a Quake modification, but it was under heavy development
and new improvements were made. Currently the developers of Xonotic
state that the game is ‘on the par with most commercial games from
2006-2007’. Which, for the Linux platform is pretty important.“Xonotic is a fast-paced shooter set in an unreal world, and
comes with a wide range of weapons, maps, various player models and
a whole bunch of community-created content. Its strong point is the
multiplayer mode, however it also includes an instant action mode
vs bots and a singleplayer campaign with bots support.”