Free & Open Source Sci-Fi Games
521 free, open-source sci-fi games — real clones and remakes you can download, inspect the source of, and modify.
Archived
Clone of Command & Conquer: Generals
Electronic Arts' official open-source Zero Hour engine and code, paired with a Steam re-release adding Workshop support for community maps.
Platforms:Windows
Stars4,721
Updated1 year ago
LicenseGPL3*
Release2024
Genre: Real-Time Strategy
Theme: Sci-Fi
Archived
Clone of Command & Conquer: Renegade
Electronic Arts' official open-source release of the Renegade engine, paired with a Steam re-release adding Workshop support for user maps.
Active
Clone of Perimeter
KD Lab's own official open-source release of the Perimeter engine, paired with a Steam re-release; online play works via LAN or GameRanger.
Platforms:Windows
Stars552
Updated2 months ago
LicenseGPL-3.0
Release2021
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Clone of Master of Orion
Remnants of the Precursors is a modernization of Master of Orion, leading one of ten races to galactic domination with streamlined play.
Platforms:WindowsLinuxOSX
Stars221
Updated3 years ago
LicenseCC-BY-NC-ND, GPL3*
Release2020
Genre: Turn-Based Strategy
Theme: Sci-Fi
Active
Original game image
Original game imageClone of Master of Orion
A reconstruction of the original 1993 DOS Master of Orion for modern systems, though this fork is no longer actively developed.
Platforms:WindowsLinuxDOS
Stars110
Updated2 months ago
LicenseGPL-2.0
Release2022
Genre: Turn-Based Strategy
Theme: Sci-Fi
Sporadic
Halted
Active
Clone of Dune 2000
An open-source RTS engine that reimagines Red Alert, Tiberian Dawn and Dune 2000, with online multiplayer and modding tools.
Platforms:WindowsLinuxOSX
Stars17,376
Updated1 month ago
LicenseGPL-3.0
Release2010
Genre: Real-Time Strategy
Theme: Sci-Fi
Active
Clone of Star Wars: Galactic Battlegrounds
A free engine clone of Age of Empires' Genie Engine; it needs the original game assets, and gameplay is being rebuilt.
Platforms:Linux
Stars14,432
Updated1 month ago
LicenseUnknown
Release2013
Genre: Real-Time Strategy
Theme: Sci-Fi
Active
Original game image
Original game imageClone of Half-Life 2
Valve's official SDK release with the game code for Half-Life 2, HL2: Deathmatch, and Team Fortress 2, for building mods.
Halted
Original game image
Original game imageClone of Quake 3
id Software's official GPL source release for Quake III Arena, including its full renderer, game code, and Q3Radiant editor.
Halted
Original game image
Original game imageClone of Doom 3
id Software's Doom 3 BFG Edition GPL source release, code only, omitting features like Steam integration and Bink video playback.
Halted
Active
Clone of Total Annihilation
Beyond All Reason is an open-source real-time strategy game built on the Recoil engine, combining a lobby launcher with Lua-based game code.
Platforms:WindowsLinux
Stars4,207
Updated1 month ago
LicenseUnknown
Release2019
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Clone of Total Annihilation
An open-source real-time strategy engine descended from Total Annihilation, for Windows, Linux, and macOS.
Platforms:WindowsLinuxOSX
Stars3,997
Updated2 years ago
LicenseUnknown
Release2008
Genre: Real-Time Strategy
Theme: Sci-Fi
Active
Original game image
Original game imageClone of Warzone 2100
Warzone 2100, GPL-licensed since 2004, is a free open-source 3D RTS with campaign, online multiplayer, and JavaScript modding.
Platforms:WindowsLinuxOSX
Stars3,954
Updated1 month ago
LicenseGPL-2.0
Release2010
Genre: Real-Time Strategy
Theme: Sci-Fi
Active
Clone of Space Station 13
An open-source remake of SS13 built on a custom C# engine, with heavily moddable community servers.
Active
Clone of Spore
An open-source evolution sim where you guide a species from a single cell through mutation-driven natural selection.
Platforms:Windows
Stars3,706
Updated1 month ago
LicenseUnknown
Release2012
Genre: Simulation
Theme: Sci-Fi
Active
Clone of S.T.A.L.K.E.R.
A community-improved X-Ray Engine for S.T.A.L.K.E.R. with 64-bit support, bug fixes and Linux/macOS ports.
Platforms:Windows
Stars3,559
Updated1 month ago
LicenseUnknown
Release2014
Genre: FPS
Theme: Alternate Historical
Active
Clone of Jak and Daxter: The Precursor Legacy
A native PC port of the Jak and Daxter trilogy, decompiled from the original GOAL code; requires your own PS2 discs.
Halted
Active
Sporadic
Active
Clone of Wipeout
A work-in-progress, asset-free re-implementation of the 1995 PSX racer Wipeout for SDL2, Sokol, and web.
Active
Active
Clone of Astro Chicken
An open-source engine reimplementation that lets classic point-and-click adventures and RPGs run on modern platforms.
Active
Clone of Doom
A source port that reproduces the original DOS Doom, Heretic, Hexen, and Strife with their original bugs intact on modern systems.
Active
Sporadic
Clone of X-COM: UFO Defense
A playable open-source clone of UFO: Enemy Unknown and Terror from the Deep with extensive mod support.
Halted
Original game image
Original game imageClone of Quake 2
id Software's official source for the 2023 Quake II Rerelease's game-logic DLL, merging all four expansion codebases into one.
Sporadic
Active
Clone of Star Fox 64
It includes no copyrighted assets and requires you to provide a supported copy of the game.
Stars2,077
Updated1 month ago
LicenseCC0-1.0
Release2024
Genre: Shooter
Theme: Sci-Fi
Active
Clone of Athena Crisis
Athena Crisis is an MIT-licensed turn-based strategy game whose core code — engine, AI, rendering, and map editor — is open-core.
Platforms:Web
Stars1,981
Updated2 months ago
LicenseUnknown
Release2024
Genre: Turn-Based Tactics
Theme: Sci-Fi
Active
Active
Clone of Doom 3
RBDOOM-3-BFG is a deeply modernized DOOM 3 BFG source port with PBR rendering and DX12/Vulkan support.
Halted
Active
Original game image
Original game imageClone of Dune 2
A playable open-source re-creation of Westwood's Dune II that runs natively on many systems using the original data files.
Platforms:WindowsLinuxOSX
Stars1,688
Updated2 months ago
LicenseGPL-2.0
Release2012
Genre: Real-Time Strategy
Theme: Sci-Fi
Sporadic
Clone of Command & Conquer: Generals
An early-stage, not-yet-playable open-source re-implementation of EA's SAGE engine, targeting C&C: Generals and Zero Hour.
Platforms:WindowsLinuxOSX
Stars1,635
Updated7 months ago
LicenseUnknown
Release2017
Genre: Real-Time Strategy
Theme: Sci-Fi