Classic arena first person shooter

ReC98 source port of the first Seihou Project game

A Quake mod based on the retro shooter SPRAWL

Tank digging battle game

Fast paced, first person strategy game

Open source first person shooter

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

Leading the way in newschool multiplayer Doom online

Source port for Build engine games

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

dhewm 3 is a Doom 3 GPL source port

Game engine for Return to Castle Wolfenstein

Free agile arena shooter

The Free and Fast Arena Shooter

Shoot and survive

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

Epic story-driven FPS running on the Build Engine

Open Source voxel shooter

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

The orb ponderer's arena first-person shooter

A modernization effort of DOOM-3-BFG

Game engine for Classic Doom

First-person shooter game

Modern cross-platform port of the Descent engine

Free fast paced arena shooter

EDuke32 is an awesome, free homebrew game engine

Open source first person shooter

Top-down shooter action RPG

FPS aim trainer

a modern QuakeWorld client focused on competitive online play