Source port for Build engine games

Leading the way in newschool multiplayer Doom online

Shoot and survive

ReC98 source port of the first Seihou Project game

The Free and Fast Arena Shooter

FPS aim trainer

Free fast paced arena shooter

Open source first person shooter

Open Source voxel shooter

Game engine for Classic Doom

Fast paced, first person strategy game

Epic story-driven FPS running on the Build Engine

First-person shooter game

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

A Quake mod based on the retro shooter SPRAWL

A modernization effort of DOOM-3-BFG

Top-down shooter action RPG

Classic arena first person shooter

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

The orb ponderer's arena first-person shooter

dhewm 3 is a Doom 3 GPL source port

Game engine for Return to Castle Wolfenstein

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

EDuke32 is an awesome, free homebrew game engine

Modern cross-platform port of the Descent engine

First-person shooter with cooperative in-game map editing

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

Open source first person shooter

a modern QuakeWorld client focused on competitive online play

Tank digging battle game