Nexuiz

Опенсорцная, свободная стрелялка, FPS. Нексузь, вероятно так надо произносить.
Взяли за основу движок Quake1 и хорошо так доделали/переделали.
Судя по скриншотам - весч. Работает на OpenGL под виндой, маком и линуксом.

Nexuiz is a 3d deathmatch game that has been in development since the summer of 2002. The goal of the project is to create a high quality first person shooter that can be played freely across all platforms in one package: PC, Mac, and can be even included in Linux distributions. The game is entirely open source, with the sources of the engine, gamecode, map files, and compiling tools, all included with the download, all under the GPL license.

The gameplay is deathmatch with the most excessive possible speeds and weapons, giving incredibly intense fast paced action. Along with deathmatch, there are multiple gamemodes such as team deathmatch, capture the flag, domination, and many mutators and weapon options like rocket arena and instagib. The user can fight through the single player campaign, going through over 20 levels, or play online with our server browser.

alientrap.org