Here is a list of free/libre and open source games that are available on Steam. Enjoy! Improve the list if you know another one!
Most of the time, the games here are totally FLOSS, where every assets, resource files, source code, etc are free and open-source. Some games here need an original resource file to be played (or they are included in the Steam release but not in the floss source code), even if they are on Steam. It means, some games listed here are open source game engine where you have to own a copy of the game to play it because the resources needed to play sometimes aren't open source. This list doesn't include games where the source code is open, but not free/libre.
Game on Steam | Source Code | Website
Co-operative top-down shooter game available for free. An epic bug hunt featuring a unique blend of co-op play and squad-level tactics.
Game on Steam | Source Code | GNU General Public License v3.0 | Website
From the creators of Amnesia: The Dark Descent and Dear Esther comes a new first-person horror game that will drag you to the depths of greed, power and madness. It will bury its snout into your ribs and it will eat your heart.
Game on Steam | Source Code | GNU General Public License v3.0 | Website
Amnesia: The Dark Descent, a first person survival horror. A game about immersion, discovery and living through a nightmare. An experience that will chill you to the core.
Game on Steam | Source Code | BSD 3-Clause "New" or "Revised" License | Website
Build and upgrade your personal ship to travel around a strange planet.
Game on Steam | Source Code | BSD 2-Clause License | Website | Tutorials & Help | Discord
Barony is the premier first-person roguelike with cooperative play. Cryptic items, brutal traps, and devious monsters await you. Conquer the dungeon alone, or gather a party in co-op with iconic and unusual RPG classes. Get ready to try, and die, and try again with a new dungeon every time you play!
Game on Steam | Source code | GNU General Public License v2.0 | Tutorials & Help | Website | News | Forums | Donate
The Battle for Wesnoth is an open source, turn-based strategy game with a high fantasy theme. Explore the four corners of Irdya in seventeen solo campaigns and dozens of multiplayer maps, taking part in countless adventures as you go.
Game on Steam | Source Code | License Apache 2.0 | Tutorials & Help | Website | Forums
Bitburner is a programming-based incremental game. Write scripts in JavaScript to automate gameplay, learn skills, play minigames, solve puzzles, and more in this cyberpunk text-based incremental RPG.
Game on Steam | Source Code | License Public Domain | Website | Donate
What if Breakout was the only arcade game people could make? An open-source game, written entirely on a live stream.
Game on Steam | Source Code | Donate
Steal everything you can and flee from the Burning Knight's castle in this action-packed roguelike! The game features tight bullet hell, tons of items, characters to meet... and secrets!
BYTEPATH is a replayable arcade shooter with a focus on build theorycrafting. Use a massive skill tree, many classes and ships to create your own builds and defeat an ever increasing amount of enemies.
Game on Steam | Source Code | Website | Tutorials & Help | Forums | Donate
The epitome of a modern traditional roguelike: with turn-based play and a RPG-like skill progression system, it hearkens back to some of the major aspects of this genre. This game has an incredible depth, with a deep inventory system, vehicles and boats, NPCs with their own stories, and more.
Game on Steam | Source Code | Tutorials & Help | Website
Cendric combines 2D RPG and Platformer elements in one indie game, featuring both a sidescroller and top-down view. The player explore a world by completing levels and quests, following the story of a boy with no memory and discovering the magical but dangerous world of Admantris.
A challenging puzzle-platformer where each jump is a puzzle.
The Psychedelic Tunnel-Runner.
Game on Steam | Tutorials & Help | (incomplete) Source Code | Website
WARNING: THIS GAME ISN'T AVAILABLE ON STEAM ANYMORE, BUT YOU CAN STILL DOWNLOAD IT FROM THE WEBSITE.
Crystal Picnic is a lighthearted and colorful tribute to the classic era of action RPGs! Join a sarcastic gardener and a wannabe knight as they journey across the kingdom chasing after ants who stole magic crystals from the castle.
Game on Steam | Tutorials & Help | Source Code | Website | Forums
DDraceNetwork is a cooperative racing mod of Teeworlds. What started as a simple mod is now a big cooperative platformer experience! Choose from hundreds of available maps, race your way to the finish line and help your friends. Collaborate and compete with players all over the world.
In this 2D, short narrative-based game, you assume the role of the Grim Reaper... on an office job. Your job is to decide which people are going to live or die. The consequences of your choices are yours to bear, while the mystery of your incarnation awaits revelation!
Game on Steam | Source Code | Website
Pilot your ship in the seamless open world made of space, planets, and more. Find new ships and equipment, find allies and beat all the enemies in this open source space shooter!
Game on Steam | Source Code | Website
Build a colony of ruthless capitalist Dwarves in a strange fantasy land.
Game on Steam | Tutorials & Help | Source code | Website | News
Endless Sky is a 2D space trading and combat game inspired by the classic Escape Velocity series. Work your way up from a relatively wimpy shuttle, cargo ship, or fighter, to a highly upgraded and customized flagship or to a massive fleet of warships or freighters.
Game on Steam | Source Code | Website | Donate
Epicinium is a strategy game where nature is a finite resource. No need to wait for your move, thanks to fast, simultaneous turns. Your economy and troops are influenced by the environment and increasingly severe weather effects. Is it worth winning a war when you end up conquering dirt and ash?
Game on Steam | Source Code | zlib License | Website
Lead your orbital battleships to victory in Flotilla! Fight, trade, and explore new planets in your journey through the galaxy. Featuring tactically rich 3D combat, flank and surprise the enemy from any direction. And when the dust settles, generate another uniquely randomized universe for a brand-spanking new adventure!
Game on Steam | Source Code | GNU General Public License v2.0 | Website | Tutorials & Help | News | Forums
FreedroidRPG is an open source sci-fi role playing game, where the player (playing as Tux) fights against hordes of bots in order to free humanity from rebel bots whom know no mercy.
Game on Steam | Source Code | GNU General Public License v2.0 | Website
To make it in Nuevos Aires, one needs nerves of silk and the filthiest of hands.
Game on Steam | Source Code | GNU AFFERO GENERAL PUBLIC LICENSE | Website
Try your hand as a global planner of a future society. Play with a wide range of technologies and policies spanning different fields and ideologies. Will you lead the world to ecological utopia or planetary ruin?
Game on Steam | Source Code (Mirror on GitHub) | GNU General Public License v2.0 | Website | Tutorials & Help | News | Forums
Turn-based strategy, artillery, action and comedy game, featuring the antics of pink hedgehogs with attitude as they battle from the depths of hell to the depths of space.
Game on Steam | Source Code | BSD 3-Clause "New" or "Revised" License | Website | Tutorials & Help
Trade your wares and eliminate the competition in a cutthroat world. Buy new ships and stations to mine and haul resources. Explore the vast emptiness of space.
Hooksharks is a local multiplayer game about glory, and most of all, battling sharks with giant hooks attached to them.
Game on Steam | Source Code | Website | Donate
A tactical puzzle/roguelike on a hyperbolic plane.
Following in the footsteps of Dwarf Fortress and Gnomoria, this game aims to provide the best experience of both worlds. The graphics and accessibility of Gnomoria and the depth and rich content of Dwarf Fortress.
Game on Steam | Tutorials & Help | Source code | Website | News
Ambitious dungeon simulator with roguelike and RPG elements. Take the role of an evil wizard and study the methods of black magic. Equip your minions and explore the world, murder innocent villagers and burn their homes. Build your dungeon, lay traps and prepare for an assault of angry heroes.
Koi Farm is a game about playing with koi ponds. Explore an infinite number of procedurally generated koi patterns by crossbreeding your fish, and discover new mutations as you go along.
Game on Steam | Source Code | Website
Lazy Chess is a new non-profit chess game that narrows your choices down to the best 2 possible moves per turn. The moves provided can always win the game, but how strong are your decisions? Fewer moves. More fun.
Game on Steam | Source Code (classic) | Source Code (community) | Licence GPLv2 | Facebook
Originally released in 1994, Little Big Adventure, also known as Relentless: Twinsen’s Adventure, is an action-adventure RPG designed by Frédérick Raynal. The source code for both orginal games was released in 2021 under floss license, however the assets are not floss.
Game on Steam | Source Code (classic) | Source Code (community) | Licence GPLv2 | Facebook
The sequel of Little Big Adventure. After saving the world from the evilish Doctor Funfrock, Twinsen is now ready to face a new threat coming from outer space. The source code is floss, but the assets are not floss.
Game on Steam | Source Code | Website
Marvellous Inc. is a programming puzzle game, where you program robots to solve tasks.
A free open-source circle-clicking rhythm game practice client for osu! beatmaps with Virtual Reality support. McOsu is developed separately from and has no direct affiliation with osu! or ppy Pty Ltd.
Game on Steam | Tutorials & Help | Source code | Website | News | Forums | Donate
MegaGlest is an open source cross-platform 3D real-time strategy (RTS) game, where you control the armies of one of seven different factions: Tech, Magic, Egypt, Indians, Norsemen, Persian or Romans. The game is setup in one of 17 naturally looking settings, which -like the unit models- are crafted with great appreciation for detail.
Game on Steam | Source code | Website | Tutorials & Help
An open-ended tower-defense game with a focus on resource management.
Game on Steam | (incomplete) Source code | Website
WARNING: THIS GAME ISN'T AVAILABLE ON STEAM ANYMORE, BUT YOU CAN STILL DOWNLOAD IT FROM THE WEBSITE.
Monster RPG 2 is a fantasy quest that spans continents and worlds and lets you take a simple villager and develop her into a hero with the power to save her world.
Game on Steam | Source Code | Website
Naev is a game about space exploration, trade and combat. Players travel the galaxy and earn money by trading, fighting and performing missions.
Game on Steam | Source code | Website | News | Forums
A multiplayer survival game of parenting and civilization building. Get born to another player as your mother. Live an entire life in one hour. Have babies of your own in the form of other players. Leave a legacy for the next generation as you help to rebuild civilization from scratch. Updated weekly.
Game on Steam | Source Code | Website | Donate
Manga are comics created in Japan. The problem for most people is, as they're made in Japan they're only produced in Japanese; someone has to translate them to English! Is one man able to accomplish this? Is there more to his team's relationships other than business? Can everything in a translator's life be simple and clear?
Game on Steam | Source Code | License AFL | Website
Open Hexagon is a FOSS clone of Super Hexagon, a minimal action game. A fast-paced adrenalinic arcade game that's easy to learn but hard to master!
Game on Steam | Source Code | Tutorials & Help | Website | Forums | Donate
OpenTTD is a business simulation game in which players earn money by transporting passengers and cargo via road, rail, water, and air. It is an open-source remake and expansion of the 1995 Chris Sawyer video game Transport Tycoon Deluxe.
Game on Steam | Source Code | Website
Penumbra: Overture is a first person survival horror game, emphasizing on survival and problem solving instead of mindless violence and gore.
Game on Steam | Source Code | GNU General Public License v3.0 | Website
When you have a top-of-the-line hacking deck armed with a 56.6k modem and a staggering 256k RAM, it means just one thing: you answer only to the highest bidder.
Game on Steam | Source Code | Website | Donate
Quaver is a community-driven and open-source competitive rhythm game with two game modes and online leaderboards. Create your own maps or challenge the world in online multiplayer matches.
Game on Steam | Source Code | Website | Forums | Donate
Building on over 12 years of gameplay design, Red Eclipse 2 focuses on fast paced, agile, easily accessible first person shooter gameplay. For creators, the full power of the Tesseract engine is at your fingertips in the included realtime multiplayer editor.
Game on Steam | Source Code | Website | Forums
Relic Hunters Zero is a game about shooting evil space ducks and evil space turtles with tiny cute guns. It’s fast, it’s tactical, and feels delicious and smooth to play. Unlock new weapons, characters and relics to defeat the Ducan Commander.
Game on Steam | Source Code | GNU General Public License v3.0 | Website | Forums
In ROTA gravity bends beneath your feet! Move blocks and twist gravity to solve puzzles. Collect all 50 gems and explore 8 vibrant worlds!
Game on Steam | Source Code | Website | News | Forums
Enter a unique science fantasy MMORPG and dive into a unique organic living world !
Game on Steam | Source Code | Website | News | Forums
Screeps is an open source MMO RTS sandbox game for programming enthusiasts, wherein the core mechanic is programming your units AI. You control your colony by writing JavaScript which operates 24/7 in the single persistent open world filled by other players on par with you.
Game on Steam | Source Code | Website
Solve puzzles by designing an AI for a team of selfless heroes. Test your algorithm, optimize it, and emerge victorious from the dungeon!
Game on Steam | Source Code | Website
Session Seven is a free point & click adventure game in which you play as Ryan, an estranged father and husband who has just awoken, beaten, bruised, and alone in a locked cellar.
Game on Steam | Source Code | Website
shapez.io is a game about building factories to automate the creation and processing of increasingly complex shapes across an infinitely expanding map.
Game on Steam | Source Code | Website | News | Donate
Shattered Pixel Dungeon is a traditional roguelike dungeon crawler that's simple to start but hard to master!
Game on Steam | Source Code | Tutorials & Help | Website | News | Forums
Simutrans is a freeware and open-source transportation simulator. Your goal is to establish a successful transport company. Transport passengers, mail and goods by rail, road, ship, and even air. Interconnect districts, cities, public buildings, industries and tourist attractions
Game on Steam | Source Code | Website
Play the classic that transcends generations.
SNKRX is an arcade shooter roguelite where you control a snake of heroes that automatically attack nearby enemies. Combine different heroes to unlock class bonuses and create unique builds, and steer your unstoppable party as they ravage through endless waves of enemies.
Game on Steam | Source Code | License GPLv3 | Tutorials & Help | Website | Donate
Discover a space strategy game filled with conquest, betrayal and subterfuge. Build alliances, make enemies and fight your way to victory and galactic domination. Will you conquer the galaxy?
Game on Steam | Source Code | Website
Soldat is a unique 2D (side-view) multiplayer action game. It has been influenced by the best of games such as Liero, Worms, Quake, and Counter-Strike and provides a fast-paced gaming experience with tons of blood and flesh.
Game on Steam | Source Code | License MIT | Tutorials & Help | Website | News | Forums | Donate
Disasters, enemies, and incompetence conspire to make each shift aboard the station a unique and hellish experience. Sign up today to explore intricate game mechanics and enjoy limitless player interaction! (Nanotrasen Inc. is not responsible for injury, death, or worse).
Game on Steam | Source Code | License MIT | Website
Massive scale 4X-RTS set in space. Control hundreds of planets, manipulate galactic politics, research numerous advanced technologies, and command thousands of units and hundreds of planets in your quest for galactic dominance.
Game on Steam | Source Code | License GPLv3 | Website | News | Forums | Donate
Classic 2D jump'n'run sidescroller featuring Tux the penguin. Run and jump through multiple worlds, fighting off enemies by jumping on them, bumping them from below or tossing objects at them, grabbing power-ups and other stuff on the way.
Game on Steam | Source Code | License GPLv3 | Tutorials & Help | Website | News | Forums | Donate
Tales of Maj’Eyal is a roguelike RPG, featuring tactical turn-based combat and advanced character building. Play as one of many unique races and classes in the lore-filled world of Eyal, exploring random dungeons, facing challenging battles, and developing characters with your own tailored mix of...
Game on Steam | Source Code | License CC-BY-SA 3.0 | Website | News | Forums
Teeworlds is a free online multiplayer game, available for all major operating systems. Battle with up to 16 players in a variety of game modes, including Team Deathmatch and Capture The Flag. You can even design your own maps!
Game on Steam | Source Code | License GPLv3 | Donate
Termite is a psychedelic real-time action strategy experience. You are the leader of a termite hive with three objectives: collect food, produce ants and destroy alien colonies.
Game on Steam | Source Code | Tutorials & Help | Website | News | Forums | Donate
The Castle Doctrine is a massively-multiplayer game of burglary and home defense. It's 1991, and things are bad. You're a guy with a house and family. Other players are coming to take what's yours. Build security to stop them. Study their houses, buy tools, and break in to take what's theirs.
Game on Steam | Source Code | Tutorials & Help | Website | Forums
Explore thirteen different castles, overcoming a variety of puzzles and traps while you attempt to escape.
Game on Steam | Source Code | Donate
The Colorful Creature is difficult platformer with puzzle color mechanics. Play over 300 levels with diverse gameplay that have many items and hazards, in-game level editor, local multiplayer, endless run, customizable skins & hats, steam workshop and more!
Game on Steam | Source Code | GNU General Public License v3.0 | Website | Forums | Tutorials & Help | Items made by other players
The Powder Toy is a classic physics sandbox game, which simulates air pressure and velocity, heat, gravity and a countless number of interactions between different substances
Game on Steam | Source Code | Website
Explore the deepest SECRETs™ of the Tremendous Corporation®. Find out what happened to indie devs and save the gaming industry!
Game on Steam | Source Code | GNU General Public License v2.0 | Website
Explore the world of Thirty Flights of Loving through a first-person short story. Take a deep dive with high-flying schemers, lovelorn criminals, and more stray kittens than you can shake a stick at.
Game on Steam | Source Code | Tutorials & Help | Website | News | Forums | Donate
An evolution simulation game. Take control of your species in the environment and edit your species as a whole. Compete with other evolving species for resources on an alien planet.
Mod on Steam | Source Code | Website | Donate
Dig, Fight, and Build your way through the world of player-created mods on Terraria with tModLoader - this DLC makes modding Terraria a reality!
Note: In order to use this mod, you need to own Terraria on the Steam. Terraria is not FLOSS, but proprietary software.
Game on Steam | Source Code | Website
Tomatenquark is a multiplayer & singleplayer first person shooter, a community homage to Cube 2: Sauerbraten.
Trigger Time is a story-driven, top-down Shoot 'em up with a fun gravity gun and physics puzzles to solve. Blast your way through 9 levels filled with enemies, hazards and bizarre bosses. Along the way you'll take control of vehicles, pick up weapons, items and boosters.
Game on Steam | Source Code | Website
A truly free and open source multiplayer shooter, no strings attached. Have casual deathmatch matches on various scenarios. Build your own levels with the ingame editor and assets that come with the game, or just play around and use it as a sandbox.
Game on Steam | Source Code | Website
Vulture for NetHack is an isometric graphical interface for the roguelike engine: NetHack, the most celebrated member of the ancient and honorable family of games descended from Rogue and hence known as “roguelike”: bare-bones ASCII-graphics adventures set in randomly generated dungeons, in which the player fights monsters and collects items until he or she dies.
Game on Steam | Source Code | Website
Warfork is a demanding fast paced first person shooter with a focus on speed, aim, movement, and above all competitive play.
Game on Steam | Source Code | Website | Forums
Wyrmsun is a real-time strategy game which features elements of mythology, history and fiction with retro-style graphics, 3 playable civilizations, story-based scenarios, playable on a huge map. There are dozens of units, buildings and technologies
Game on Steam | Source Code | Website | Forums | Donate
Zero-K is an expansive Real Time Strategy game. Fight epic battles over land, air and sea on 100s of maps. Manipulate the terrain and throw units around. Explore an abandoned galaxy, solo or co-op, in 70 campaign missions. Hop online for a tense 1v1 or massive battles with up to 32 players.
- Addons supported/extendable?
- Add FLOSS software available on Steam
- Add more FLOSS mods (only 1 listed for now)
Platforms supported?- Add license (and specifications for assets, most of the time they aren't floss)?
I found a lot of references thanks to this curator and this one as well, but I found some others somewhere on the internet, I can't remember where... Thanks to all the contributors who added Games, Mods and Software via Issues or Pull Requests.