Open Source Game Clones

This site tries to gather open-source reimplementations of great old games in one place. If you think that some information is missing or have any suggestions - send a pull request via Github or a mail to me.

Since all these projects are open-source you can help them and make this world a better place. Or at least you can play something to appreciate the effort people put in them.

Similar resources: check out Liberated Games, which specializes on commercial games, which were made free, and Free Gamer, a blog dedicated to open source game news.

All games that were added in last month are highlighted like this.

List of complete clones

Some of these games aren't reimplementations but evolution of original ones, which were eventually open sourced.
SCUMM #
ScummVM - very active development, C++. List of supported games is here (repository).
Abuse #
Abuse - development halted, playable, C++, Lisp (repository).
Age of Empires II #
OpenAge - active development, runnable (not playable yet), requires original files, C++11, Python, SDL (repository).
Alien 8 #
Alien 8 - development halted, playable, C.
Alone in the Dark #
Alone in the Dark 2
Jack in the Dark
Alone in the Dark 3
Free in the Dark - development halted, C, GPL (repository).
Another World (video game) #
New RAW - development halted, C++, GPL (repository).
Ares #
Antares - active development, C++, GPL3, playable (repository).
Arx Fatalis #
Arx Libertatis - active development, C++; needs original game files (repository).
Ascendancy #
Starlane Empire - development halted, C++, GPL (repository).
Asteroids #
Maelstrom - development halted, playable, C.
Atomix #
Atomiks - C, playable.
Baldur's Gate series #
Icewind Dale series
Planescape: Torment
GemRB - active development, C++ (repository).
Battle City #
Battle City - sporadic development, playable, C++ (repository).
Bermuda Syndrome #
Bermuda Syndrome - sporadic (or halted) development, playable.
Betrayal at Krondor #
xBaK - sporadic (or halted) development, playable.
Blake Stone: Planet Strike #
bstone - active development, playable, c++.
Blood #
Blood Crossmatching (EDuke32 vanilla) - active development (repository).
Transfusion - sporadic development, playable (repository).
Bolo #
orona - development halted, playable, HTML5 (repository).
Bomberman #
SDL Bomber - development halted, playable, C.
Boulder Dash #
Rocks n diamonds - sporadic development, playable, C.
Caesar 3 #
CaesarIA - active development, C++, somewhat playable.
Cannon Fodder #
OpenFodder - development halted, resources are loaded / maps drawn, C++ (repository).
Carmageddon #
OpenC1 - sporadic development, playable, needs game data, C# (repository).
Catacomb II #
CatacombSDL - playable, needs game data, C (repository).
Cave Story #
NXEngine - sporadic development, playable, needs game data (but it's free!).
Chip's Challenge #
Tile World - playable, C.
Tile World 2 - playable, C (repository).
ChuChu Rocket! #
Duck Marines - active development, playable, Lua, music is CC-BY-NC-ND (repository).
Clonk #
OpenClonk - active development, C++ (repository).
Colonization #
FreeCol - active development, Java (repository).
Commander Keen Series #
Commander Genius - active development, C++ (repository).
Command & Conquer #
Command & Conquer: Red Alert
Dune 2000
OpenRA - active development, C# (repository).
Creatures #
Open Creatures - development halted, forks present, C++, LGPL.
Curse of the Azure Bonds #
coab - sporadic development, playable, C# (repository).
C-Dogs #
C-Dogs SDL - active development, playable, C (repository).
Descent #
Descent 2
D2X - active development, C++ (repository).
DXX-Rebirth - active development, C (repository).
Diablo #
freeablo - active development, needs game data, C++ (repository).
Doom #
Doom II
Heretic
Hexen
Doomsday - active development, C (repository).
Chocolate Doom - active development, C (repository).
ZDoom - active development, C (repository).
PrBoom+ - active development, C (repository).
Odamex - active development, C (repository).
GLHeretic - C (repository).
Freedoom - free resources for Doom II, sporadic development (repository).
Doom Legacy - active development, playable, C++ (repository).
Drugwars #
Dope Wars - sporadic development, C (repository).
Duke Nukem 3D #
EDuke32 - active development, C (repository).
Dune 2 #
Dune Legacy - active development, C++ (repository).
OpenDUNE - active development, C (repository).
Dune Dynasty - active development, C (repository).
Dune II - The Maker - development halted, C++, MIT (repository).
Dungeon Keeper #
KeeperFX - active development, C; not really a clone, but a hack to make Dungeon Keeper run on recent OSes (repository).
Eye of the Beholder II #
Dungeon Eye - sporadic development, C# (repository).
The Elder Scrolls III: Morrowind #
OpenMW - active development, C++ (repository).
Fade to Black #
f2bgl - sporadic development, C++.
Flashback #
REminiscence - moderately active development.
Forsaken #
ProjectX - playable (repository).
FreeSpace 2 #
FreeSpace Source Code Project - active development, C++ (repository).
Gladiator #
Openglad - sporadic development, C++ (repository).
Glest #
Glest Advanced Engine - sporadic development, C++, playable.
Grim Fandango #
Escape from Monkey Island
Myst III: Exile
ResidualVM - active development, C++.
Grand Theft Auto 2 #
gta2net - active development, .NET (repository).
Guitar Hero #
Frets on Fire - development halted, playable, Python (look for songs on the wiki) (repository).
Frets on Fire X - active development, playable, Python (repository).
Half-Life #
Sing - development halted, C (repository).
Hardwar #
Hardwar - sporadic development, C/C++ (repository).
Hexen II #
Hammer of Thyrion - active development, C (repository).
Heroes of Might and Magic II #
fheroes2 - active development, C++ (repository).
Heroes of Might and Magic III #
Ancient Beast - active development, playable, HTML5, javascript (repository).
VCMI - active development, time-based releases, C++ (repository).
Homeworld #
Homeworld SDL - development halted, playable (repository).
Imperium Galactica #
Open Imperium Galactica - occasional development, playable, Java (repository).
Jagged Alliance 2 #
Jagged Alliance 2 - Stracciatella - active development, playable.
Jazz Jackrabbit #
OpenJazz - sporadic development, C++ (repository).
Jedi Knight II: Jedi Outcast #
JediOutcastLinux - active development, playable, C++.
Jedi Knight: Jedi Academy #
JediAcademyLinux - active development, playable, C++.
OpenJK - active development, playable, C++.
Jumpgate: The Reconstruction Initiative #
Open Jumpgate - active development, C++.
Knights and Merchants #
KaM Remake - active development, Delphi (repository).
The Lord of the Rings Volume 1 #
Lord of the Rings game engine - development halted, playable, C (repository).
Liero #
OpenLiero - development halted, C++ (repository).
OpenLieroX - active development, C++ (repository).
Gusanos - development halted, seems to be playable (repository).
Lode Runner #
XScavenger - development halted, playable, C.
Log!cal #
Orbium - sporadic development, HTML5/JS, playable, GPL2 (repository).
Missile Command #
Missile Command - development halted, playable, Lua (repository).
Mad TV #
TVTower - active development, BlitzMax, C (repository).
Outrun #
Cannonball - active development, playable, C++, needs game data (repository).
Oxyd #
Enigma - active development, C++ (repository).
Portal #
glPortal - somewhat active development, C++, playable (repository).
glPortal2 - somewhat active development, C++.
Prince of Persia #
FreePrince - C, halted development, mostly playable.
Quake 3 #
ioquake3 - active development, C (repository).
OpenArena - sporadic development, C (repository).
Marathon #
Marathon 2
Marathon Infinity
Aleph One - active development, C++ (repository).
Mario World #
Secret Maryo Chronicles - sporadic development, C++ (repository).
Master of Orion 2 #
OpenMOO2 - moderately active development, Python (repository).
M.A.X. #
Mechanized Assault and eXploration Reloaded - moderately active development, C++ (repository).
Mega Lo Mania #
Gigalomania - moderately active development, playable, C++ (repository).
Minecraft #
Minetest - active development, C/C++ (repository).
Manic Digger - moderately active development, C# (repository).
Gnomescroll - development halted, playable, C++, GPL3 (repository).
Terasology - active development, playable, Java, Apache License (repository).
Nebulus #
Toppler - sporadic development, C++.
Neverwinter Night #
Neverwinter Nights 2
Star Wars: Knights of the Old Republic
Star Wars: Knights of the Old Republic II – The Sith Lords
Jade Empire
Sonic Chronicles: The Dark Brotherhood
The Witcher
Dragon Age: Origins
Dragon Age II
xoreos - sporadic development, not playable, C++ (repository).
One Must Fall: 2097 #
OpenOMF - active development, single player, 2 player and network play are playable, needs free resources from omf2097.com (repository).
Panzer General #
OpenGeneral - sporadic development, C++.
Open Panzer - active development, HTML5 (repository).
LGeneral - development halted (or very sporadic), playable, C (repository).
Paradroid #
FreedroidClassic - development completed, C.
Nighthawk - development halted, playable, C++ (repository).
Pushover #
Pushover - moderately active development, C++, playable (repository).
Redneck Rampage #
erampage (EDuke32 fork) - active development, C (repository).
Rick Dangerous #
xrick - halted development, playable, C.
Rise of the Triad #
Rise of the Triad for Linux - sporadic development, C (repository).
The Adventures of Robbo #
Robbo - active development, JavaScript, playable (repository).
Scorched Earth #
Atomic Tanks - sporadic development, playable.
Strike Commander #
libRealSpace - active development, C++ (repository).
RollerCoaster Tycoon #
FreeRCT - active development, C++ (repository).
RollerCoaster Tycoon 2 #
OpenRCT2 - active development, C, GPL3 (repository).
Seven Kingdoms #
Seven Kingdoms: Ancient Adversaries - active development, C++ (repository).
Siege #
FreeSiege - sporadic development, C++, playable (repository).
Silencer #
zSILENCER - playable, C++ (repository).
Silent Hunter 4 #
Danger from the Deep - sporadic development, C++ (repository).
SimTower #
OpenSkyscraper - active development, C++, playable (repository).
SingStar #
UltraStar Deluxe - active development, Object Pascal, playable (repository).
Sopwith #
SDL Sopwith - development halted, playable, C (repository).
Star Control 2 #
The Ur-Quan Masters - active development, C (repository).
Starcraft #
Stargus - moderately active development, C++/Lua (repository).
Stunts #
Ultimate Stunts - moderately active development, C++ (repository).
Super Mario #
Mega Mario - development halted, playable, C++.
Super Methane Brothers #
Super Methane Brothers - development halted, C++, playable.
Syndicate #
FreeSynd - active development, C++ (repository).
Syndicate Wars #
Syndicate Wars Port - playable (no network support), active newsgroup (no repo - no idea about development).
The Castles of Dr. Creep #
DrCreep - development completed, C++ (repository).
The Last Ninja Remix #
LastNinja - playable, sporadic development, C++ (repository).
The Settlers #
Freeserf - active development, playable, C (repository).
The Settlers II #
Return to the Roots - active development, C++ (repository).
Tempest #
Arashi-JS - development halted, javascript (repository).
Tetris Attack #
Panel Attack - active development, Lua, playable, basic networking support (repository).
Crack Attack! - development halted, C++, playable, networking support (repository).
Theme Hospital #
CorsixTH - active development, time-based releases, C++, Lua, SDL 2 (repository).
Titus the Fox #
Moktar
OpenTitus - sporadic development, C, SDL (repository).
Total Annihilation #
Spring - active development, C++, Java, Python (repository).
Total Annihilation 3D - moderately active development, C++ (repository).
Tomb Raider #
OpenRaider - active development, C++.
OpenTomb - active development, C++ (repository).
Touhou #
PyTouhou - active development, Python (repository).
Taisai Project - development halted, C, playable (repository).
Transport Tycoon #
Transport Tycoon Deluxe
OpenTTD - active development, C++, extremely playable (repository).
Turrican #
Hurrican - development halted, playable (Makefile needs edits to compile on Linux), C++.
Tyrian #
OpenTyrian - moderately active development, C (repository).
Ultima Online #
Iris2 - development halted, playable (repository).
Ultima IV #
xu4 - active development, C++ (repository).
Ultima VI #
The Savage Empire
Martian Dreams
Nuvie - active development, C++ (repository).
Ultima VII #
Exult - moderately active development, C++ (repository).
Ultima VIII #
Pentagram - sporadic development, C++ (repository).
Warcraft #
Wargus - moderately active development, C++/Lua (repository).
Warzone 2100 #
Warzone 2100 - active development, C++ (repository).
Wing Commander: Privateer #
Privateer - Gemini Gold - moderately active development, C++ (repository).
Wolfenstein: Enemy Territory #
ET: Legacy - active development, C, C++, Lua; needs original game files (repository).
World of Goo #
OpenGoo - active development, not playable (repository).
X-COM: UFO Defence #
UFO: Enemy Unknown
OpenXcom - active development, C++ (repository).
UFO2000 - development halted, playable, C++ (repository).
Legend of Zelda #
Solarus - active development, C++/Lua (repository).
Z #
The Zod Engine - active development (repository).
Elasto Mania #
X-Moto - active development, playable, C++.

Inspired by original game series

Age of Empires #
0 A.D. - active development, C++ (repository).
Anno series #
Unknown Horizons - active development, Python (repository).
Battle Isle series #
Crimson Fields - development halted, playable, C++ (repository).
Advanced Strategic Command - playable, sporadic development, C++, GPL2 (repository).
Battle Zone #
BZFlag - active development, C++ (repository).
Civilization II #
Freeciv - active development, C (repository).
Play Freeciv! - active development, online browser game, C, Java, JavaScript (repository).
C-Evo - playable, Delphi (repository).
Diablo #
Summoning Wars - active development, C++, Lua (repository).
FreedroidRPG - active development, C, Lua, Python (repository).
Flare - active development, C++ (repository).
DEFCON #
Dupocracy - active development, HTML5 (repository).
Dungeon Keeper #
OpenDungeons - active development, C++ (repository).
Guitar Hero #
SingStar
Dance Dance Revolution
Performous - active development, C++, playable (repository).
Elite #
Oolite - active development (repository).
Escape Velocity #
Naev - active development, C (repository).
Frontier: Elite II #
Pioneer - active development, C++ (repository).
Lemmings #
Pingus - active development, C++ (repository).
Lix - sporadic development, playable, C++ (repository).
Mario Kart #
SuperTuxKart - active development, C++, playable (repository).
Master of Orion Series #
FreeOrion - moderately active development, C++ (repository).
Microsoft Flight Simulator #
FlightGear - active development, C++ (repository).
Similar to Natural Selection #
Unvanquished - active development, C (repository).
Tremulous - no development, C (repository).
Nexuiz #
Xonotic - active development, playable, C (repository).
RPG Maker #
EasyRPG - active development, C++ (repository).
Simcity #
LinCity - moderately active development, C++ (repository).
Micropolis - active development, C++/Python.
The Settlers #
The Settlers II
Widelands - active development, C++, Lua, Python (repository).
Thief #
The Dark Mod - active development, playable, C++ (repository).
Sokoban #
CavePacker - playable, active development, C, SDL, GPL3 (repository).
Sonic the Hedgehog #
Open Surge - sporadic development, C (repository).
Sonic Robo Blast 2 - active development, C, Lua (repository).
Super Hexagon #
Open Hexagon - active development, playable, C++11 (repository).
Super Mario #
Super Mario War - development halted, playable, C++ (repository).
SuperTux - playable, active development, C++, SDL, GPL3 (repository).
Transport Tycoon Deluxe #
Simutrans - active development, C++ (repository).
Tribal Hero #
Danger Zone - active (somewhat sporadic) development, Java, not yet playable (repository).
Puzzle Bobble #
Frozen Bubble - sporadic development, Perl (repository).
Crimsonland #
Violetland - development halted, playable, C++ (repository).
Worms Series #
Hedgewars - active development, Pascal/C++/Haskell (repository).
WarMUX - sporadic development, C++ (repository).
UGH! #
CaveExpress - playable, active development, C, SDL, GPL3 (repository).
X-COM Series #
UFO: Alien Invasion - active development, C (repository).
XOR #
XorCurses - sporadic development, completed (repository).
XorGramana - development completed.
Legend of Zelda #
Open Zelda - sporadic development, C++, playable (repository).