Lincity - A City Simulation Game
Pingus
Yo Frankie! – Apricot Open Game Project
OpenCity, another 3D city simulator
OpenCity, another 3D city simulator. OpenCity is cross platform and open source. Download it now for free.
OpenArena
Unknown Horizons
Red Eclipse - A free arena shooter featuring parkour
Simutrans Transport Simulator
Simutrans is a freeware and open-source transportation simulator.
Pioneer - space adventure game
OpenClonk
Cataclysm: Dark Days Ahead
Official homepage of Cataclysm: Dark Days Ahead open source turn-based survival RPG development project. Hosts downloads of game and links to community sites...
Warsow
Set in a futuristic cartoonish world, Warsow is a completely free fast-paced first-person shooter (FPS) for Windows, Linux and macOS.
Mindustry
A sandbox tower-defense game.
OpenTTD
An open source simulator based on the classic game Transport Tycoon Deluxe. It attempts to mimic the original game as closely as possible while extending it with new features.
Widelands.org
Warzone 2100 - Real-Time Strategy Game
Ryzom - Free to Play Open-Source MMORPG
A freedom-oriented classless MMORPG, in a Science Fantasy setting focused on Roleplay, Live Events, complex crafting and dynamic environments.
Teeworlds
OpenRCT2
OpenRCT2 is the open-source adaption of the classic hit RollerCoaster Tycoon 2. Including online multiplayer, fast-forwarding and numerous bug fixes.
Biomes — Join the community shaping a new world
Biomes is an open source sandbox MMORPG built for the web using web technologies.
Speed Dreams
Speed Dreams is a Motorsport Simulator featuring high-quality 3D graphics and an accurate physics engine, all targeting maximum realism. Initially forked from TORCS, it has now reached a clearly higher realism level in visual and physics simulation, thanks to its active development team and growing community
The Battle for Wesnoth
Xonotic: The Free and Fast Arena Shooter
Free and Fast Arena Shooter
0 A.D.: Empires Ascendant
0 A.D. is a free, open-source, historical Real Time Strategy (RTS) game currently under development by Wildfire Games, a global group of volunteer game developers.
TripleA
TripleA is a free open source turn based grand strategy game engine with play similar to Axis & Allies and Risk. Over a hundred different maps created by the community covering a wide variety of scenarios (such as WW1, WW2 and various science fiction and fantasy worlds) are available for download. TripleA supports single player vs AI, hot-seat, play by email and forum, direct online play, and a hosted lobby for live online play with other community members.
SuperTux
SuperTux is an open-source classic 2D jump’n run sidescroller game in a style similar to the original Super Mario games.
SuperTuxKart
SuperTuxKart is a 3D open-source arcade racer with a variety characters, tracks, and modes to play. Discover more…
Veloren
The Veloren devblog website
Minetest - Open source voxel game engine
FlightGear Flight Simulator