First-person shooter game

Source port for Build engine games

A Quake mod based on the retro shooter SPRAWL

dhewm 3 is a Doom 3 GPL source port

Lo sparatutto arena libero e veloce

Tank digging battle game

Epic story-driven FPS running on the Build Engine

A modernization effort of DOOM-3-BFG

Open source first person shooter

Shoot and survive

First-person shooter with cooperative in-game map editing

Fast paced, first person strategy game

Classic arena first person shooter

Top-down shooter action RPG

Modern cross-platform port of the Descent engine

Free fast paced arena shooter

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

a modern QuakeWorld client focused on competitive online play

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

Free agile arena shooter

Game engine for Classic Doom

Leading the way in newschool multiplayer Doom online

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

The orb ponderer's arena first-person shooter

Open Source voxel shooter

Open source first person shooter

Game engine for Return to Castle Wolfenstein

FPS aim trainer

EDuke32 is an awesome, free homebrew game engine

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