Free fast paced arena shooter

Shoot and survive

First-person shooter with cooperative in-game map editing

Open source first person shooter

Open source first person shooter

Dhewm 3 is a Doom 3 GPL source port

Open Source voxel shooter

Classic arena first person shooter

Game engine for Return to Castle Wolfenstein

Fast paced, first person strategy game

A Quake mod based on the retro shooter SPRAWL

Game engine for Classic Doom

The orb ponderer's arena first-person shooter

ReC98 source port of the first Seihou Project game

Epic story-driven FPS running on the Build Engine

Tank digging battle game

Free agile arena shooter

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

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

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

Modern cross-platform port of the Descent engine

FPS aim trainer

a modern QuakeWorld client focused on competitive online play

Top-down shooter action RPG

A modernization effort of DOOM-3-BFG

Fast arcade first person shooter

EDuke32 is an awesome, free homebrew game engine

Source port for Build engine games

A free first person shooter for Mac, PC and Linux

Open Source voxel shooter