Doom was the classic 3D shoot'em'up game from id Software. PrBoom is a game engine for playing Doom levels, which runs on both Windows and Linux/Unix systems. It uses the SDL graphics library. PrBoom a very faithful Doom port, with great effort taken to be compatible with as many original Doom levels and demos as possible.
The Castle is a first-person shooter game in a dark fantasy setting. Your main weapon is a sword, so the fight is mostly short-range. Three main levels are included, packed with creatures, items, and sounds. A couple of bonus levels are also available, like the classic DOOM E1M1 level reimplemented in VRML. The game engine is based on VRML, OpenGL, OpenAL, and all shadows are done by the shadow volumes approach.
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.
Q3utX Master Browser is an efficient Urban Terror game servers browser. It interrogates a "Master Browser" and retrieves all servers notified, then shows all info about game servers through an Ajax loader. It shows the server game name and type, IP address and port, server engine, current map name, number of users, and current players. It can filter based on game type.
Adanaxis is an action game where the fundamentals of space itself are changed by adding a fourth dimension to space. Initially, it's like learning to play a 3D FPS for the first time, as the hand and eye have to learn a whole new type of coordination. The gameplay involves rapidly blowing things out of the sky, with the usual assortment of enemies, allies, weapons, and power-ups, together with commercially sourced graphics, audio, and voice acting.
UProxy is a proxy for UDP protocols. UProxy was initially designed to allow users to play Unreal Tournament matches over the Internet on computers sharing a dial up connection. It could also be used by any client-server application that uses the UDP protocol and doesn't require clients to bind a fixed port. UProxy should run under Windows, Linux, or any OS which supports BSD sockets.