Epic story-driven FPS running on the Build Engine

First-person shooter game

Free agile arena shooter

Modern cross-platform port of the Descent engine

A Quake mod based on the retro shooter SPRAWL

Tank digging battle game

The Free and Fast Arena Shooter

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

Fast paced, first person strategy game

Source port for Build engine games

Open source first person shooter

Open Source voxel shooter

Open source first person shooter

EDuke32 is an awesome, free homebrew game engine

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

A modernization effort of DOOM-3-BFG

a modern QuakeWorld client focused on competitive online play

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

Free fast paced arena shooter

Game engine for Classic Doom

Classic arena first person shooter

FPS aim trainer

Leading the way in newschool multiplayer Doom online

Shoot and survive

First-person shooter with cooperative in-game map editing

dhewm 3 is a Doom 3 GPL source port

Game engine for Return to Castle Wolfenstein

Top-down shooter action RPG

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

The orb ponderer's arena first-person shooter