First-person shooter game

Modern cross-platform port of the Descent engine

Epic story-driven FPS running on the Build Engine

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

Free fast paced arena shooter

A free first person shooter for Mac, PC and Linux

Source port for Build engine games

a modern QuakeWorld client focused on competitive online play

Shoot and survive

Classic arena first person shooter

Leading the way in newschool multiplayer Doom online

A Quake mod based on the retro shooter SPRAWL

ReC98 source port of the first Seihou Project game

The Free and Fast Arena Shooter

First-person shooter with cooperative in-game map editing

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

Dhewm 3 is a Doom 3 GPL source port

FPS aim trainer

Game engine for Return to Castle Wolfenstein

Game engine for Classic Doom

EDuke32 is an awesome, free homebrew game engine

Fast paced, first person strategy game

Open source first person shooter

Open Source voxel shooter

Top-down shooter action RPG

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

Free agile arena shooter

A modernization effort of DOOM-3-BFG

Open source first person shooter

Tank digging battle game