The orb ponderer's arena first-person shooter

Leading the way in newschool multiplayer Doom online

Modern cross-platform port of the Descent engine

a modern QuakeWorld client focused on competitive online play

Open Source voxel shooter

dhewm 3 is a Doom 3 GPL source port

Epic story-driven FPS running on the Build Engine

Open source first person shooter

Shoot and survive

ReC98 source port of the first Seihou Project game

Aliens vs Humans, First Person Shooter game with elements of Real Time Strategy

Free fast paced arena shooter

FPS aim trainer

Yamagi Quake II is an alternative client for id Software's Quake II

A Quake mod based on the retro shooter SPRAWL

First-person shooter game

Source port for Build engine games

The Free and Fast Arena Shooter

A Zandronum 3.0 fork with improved netcode, configurable movement and many small tweaks

Game engine for Classic Doom

Fast paced, first person strategy game

Free agile arena shooter

A modernization effort of DOOM-3-BFG

Top-down shooter action RPG

Game engine for Return to Castle Wolfenstein

EDuke32 is an awesome, free homebrew game engine

Tank digging battle game

A modern cross‑platform port of “STAR WARS™: Dark Forces” with mod support

First-person shooter with cooperative in-game map editing

Classic arena first person shooter