Shooters

Counter-Strike 2D
Free
Free Top-Down Multiplayer Shooter.
AssaultCube
Free
A free, multiplayer, first-person shooter game.
Zandronum
Free
Leading the way in newschool multiplayer Doom online.
TrueCombat Elite
Free
A modern world total conversion of the free, popular, stand-alone third-person shooter.
Unvanquished
Free
A free, open-source first-person strategy shooter, pitting technologically advanced human soldiers against hordes of highly adaptable aliens.
Star Defender 4
Free
Cube 2: Sauerbraten
Free
A free multiplayer & singleplayer first person shooter.
Xonotic
Free
An addictive, arena-style first person shooter with crisp movement and a wide array of weapons.
3D Arcade FPS
Free
A free to play arcade first person shooter game, featuring: 6 mini arcade games, local / country / world high score YOU can be the country champion or perhaps even the world master.
All Evil Night 2
Free
Meet monsters from your nightmares.
Red Crucible: Firestorm
Free
Destroy, smash and blast your way to victory! Use advanced weapons and vehicles to dominate the battlefield.
Alien Shooter 2
Free
Invention 2
Free
Mechwarrior Online
Free
A tactical, 'Mech-based online shooter set in the rich BattleTech Universe.
The Guard of Dungeon
Free
A mad first-person shooter.
Warsow
Free
A first-person shooter designed for online play.
Alien Arena
Free
A fast, fun, and free FPS deathmatch game!
All Evil Night
Free
Invention
Free
Of Guards and Thieves
Free
Keep yourself in the shadows...or simply assault all the guards! (cit)