Vermin ExTerminator is a free multiplayer network game. It is a 2D real-time first-person shooter. Little worms (vermin) fight against each other using hand guns, rifles, grenades, or rockets. In other words, the game is mix of liero and a real-time worms. The game is written in Java with LWJGL as the OpenGL and OpenAL interface.
ProQuake is a modification to the Quake source which is specifically intended for intense deathmatch play. It is a rock solid set of enhancements to unmodified NetQuake, such as precise aim, and other small, simple changes that improve the quality of netplay enormously. ProQuake is fully compatible with standard NetQuake and Clanring CRMod++ features including team scores, match timer, and client pings.
ZDoom is an enhanced port of the official DOOM source. It features support for all Hexen editing features (including ACS, hubs, etc.), support for most BOOM editing features, freelook, jumping, and translucency support, a Quake-style console, high screen resolutions, removal of the original DOOM's limits, support for many more music formats (including MOD, IT, XM, S3M, MIDI, MP3, and MUS), better mouse support, UDP networking, and more.
Vavoom is a DOOM source port incorporating Doom, Heretic, Hexen, and a little bit of Quake. It runs on DOS, Windows, and Linux and includes many advanced features like OpenGL and Direct3D support, translucency, freelook, jumping, a client/server architecture with in-game joining, a Quake-style console, a powerful language to describe game logic (Vavoom C), and much more.
YAWn! Linux is a client for the YAWn! service, which keeps track of the names used by players of "Return to Castle Wolfenstein". Players are tracked by their unique PunkBuster GUID, and thus players cannot hide behind a fake name to play recklessly or purposely misbehave. YAWn! adds a console command to "Return to Castle Wolfenstein" that lists all players like PunkBuster does. However, this command also displays the other names that the player has used before, or (for players that use YAWn! themselves) the name and taunt-message that the player chose at registration.