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.
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Original game image
Original game imageClone of Thrust
A fully annotated 6502 disassembly of Jeremy C. Smith's 1986 BBC Micro game Thrust, reassembling to the original.
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Active
Halted
Clone of Galaforce 2
Kevin Edwards' own release of the complete 6502 assembly source for Galaforce 2, reworked to build with the modern BeebAsm toolchain.
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Original game image
Original game imageClone of Quake 3
A Quake III engine project built on Quake3e, unifying classic Quake maps and mods with widescreen UI support; development has halted.
Sporadic
Active
Clone of Elite
A documented hack of BBC Micro Elite that converts its graphics to the console's teletext Mode 7 display.
Halted
Original game image
Original game imageClone of Wipeout
The released, mostly zlib-licensed source code for H-Craft Championship, originally developed by Irrgheist, for Windows, Linux, and Android.
Halted
Halted
Original game image
Original game imageClone of Missile Command
A clone of Atari's 1980 arcade game Missile Command, built with the LÖVE framework.
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Original game imageClone of Starship Command
An enhanced 2022 update of Acornsoft's 1983 BBC Micro shooter Starship Command, with faster play and more enemies.
Halted
Clone of Alien 8
SkoolKit-based disassemblies of several 1980s Ultimate Play the Game ZX Spectrum titles, including Atic Atac and Jetpac.
Halted
Clone of Quake 2
A port of the Berserker@Quake2 engine to SDL2 for Linux and Windows, requiring the player's own Quake II game data; no longer developed.
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Clone of PaybackTime 2
An X-COM-style turn-based tactics game for MS-DOS from 1994-97, released as public domain with full source and set up for DOSBox.
Platforms:WebWindows
Stars21
Updated2 years ago
LicenseUnknown
Release2014
Genre: Turn-Based Tactics
Theme: Sci-Fi
Halted
Original game image
Original game imageClone of Seven Kingdoms II: The Fryhtan Wars
An experimental fork of the 7kfans GPL release of Seven Kingdoms II replacing DirectX/DirectPlay/DirectSound with SDL2, ENet, and OpenAL.
Platforms:Linux
Stars20
Updated10 years ago
LicenseUnknown
Release2012
Genre: Real-Time Strategy
Theme: Fantasy
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Original game image
Original game imageClone of Doom 3
A source port reproducing vanilla Doom 3: BFG Edition on the modernized BFG engine, forked from RBDOOM-3-BFG before shadow mapping.
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Original game image
Original game imageClone of Mega Man 6
A complete disassembly of the NTSC-U Mega Man 6 NES ROM that reassembles byte-for-byte, though not all code is documented yet.
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Original game image
Original game imageClone of Space Harrier
A tribute to Sega's 1985 arcade game Space Harrier, built with SDL2, recreating the first level and its snake-dragon boss fight.
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Original game image
Original game imageClone of Star Trek
A Python port of a C# rewrite of the original 1971 text-based Star Trek game.
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Original game imageActive
Original game image
Original game imageClone of Alien Breed
An in-progress C# reimplementation of Team17's Alien Breed games, with an asset editor; not yet playable.
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Clone of Star Trek: Voyager – Elite Force
A modified Quake III-based engine build for the Elite Force mod RPG-X2, with raised engine limits.
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Original game image
Original game imageClone of Star Wars: Shadows of the Empire
An in-progress decompilation of a Nintendo 64 prototype build of Star Wars: Shadows of the Empire, verified by SHA1 checksum.
HaltedOriginal game image
Original game imageClone of Ironseed
A Free Pascal port of Iron Seed's original released source code, letting it compile and run natively on GNU/Linux, with ongoing bug fixes.
Active
Clone of Starsiege
A file-format viewer/converter for reverse-engineered Dynamix game data (Earthsiege, Starsiege, Tribes, Red Baron and more).
Halted
Original game image
Original game imageClone of B.O.B.
A probably-complete source code release for B.O.B. on the SNES, sourced from romhacking.net.
Active
Original game image
Original game imageClone of Star Fox 64
A work-in-progress PSP port of Star Fox 64 built on the SF64 decompilation project.
Stars18
Updated1 month ago
LicenseCC0-1.0
Release2026
Genre: Shooter
Theme: Sci-Fi
Halted
Halted
Original game image
Original game imagePlatforms:Windows
Stars17
Updated3 years ago
LicenseMIT
Release2018
Genre: Real-Time Strategy
Theme: Sci-Fi
Active
Clone of Homeworld
Gardens of Kadesh is a fan-maintained continuation of Homeworld SDL, an earlier community port of Homeworld's 1999 source code.
Platforms:WebWindowsLinux
Stars17
Updated1 month ago
Licenseother
Release2019
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Original game image
Original game imageClone of Star Wars Jedi Knight: Jedi Academy
Raven Software and Activision's official 2003 GPLv2 source code release of Star Wars Jedi Knight: Jedi Academy, not a third-party remake.
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Clone of Master of Orion 2
A Python clone of Master of Orion II for Linux that uses the original game's data files; not yet playable.
Platforms:Linux
Stars17
Updated9 years ago
LicenseGPL-2.0
Release2015
Genre: Turn-Based Strategy
Theme: Sci-Fi
Archived
Original game image
Original game imageClone of Allegiance
Microsoft's official, unsupported source-code release for Allegiance, published as-is after the game's own servers had already shut down.
Halted
Clone of Blake Stone: Planet Strike
A 2013 public release of Blake Stone: Planet Strike's source code by its original publisher; needs the commercial data files to run.
Halted
SporadicOriginal game image
Original game imageClone of Quake 3
An open-source engine reimplementation of Quake 3 versions 1.09-1.16n, built on ioquake3/ioEF, targeting Linux and macOS.
Active
Original game image
Original game imageClone of Outpost 2
A work-in-progress Outpost 2 mod for the OpenRA engine that needs the GOG release of the original.
Platforms:WindowsLinuxOSX
Stars16
Updated4 months ago
LicenseGPL-3.0
Release2020
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Original game image
Original game imageClone of Phantasy Star
A deprecated remake of Sega's Phantasy Star whose author points users to JLud2D instead.