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.
Active
Clone of Star Trek: Voyager – Elite Force
A native Android port of the Star Trek: Voyager - Elite Force single-player campaign; bring your own game data.
Halted
Halted
Original game image
Original game imageClone of Heavy Metal: F.A.K.K. 2
fakk2-rework is a proposed modernization for Heavy Metal: F.A.K.K. 2's source, with ideas like CMake, cross-platform, and ioquake3 porting.
Halted
Original game image
Original game imageClone of FreeSpace 2
An Android port of Freespace 2, which the project calls an old 3D space simulator game.
Stars14
Updated10 years ago
LicenseUnknown
Release2016
Genre: Action
Theme: Sci-Fi
Halted
Clone of Kiloblaster
A Linux/SDL port of Kiloblaster that reproduces its music via a bundled DOSBox OPL synth emulator and libgamemusic.
Halted
Sporadic
Halted
Clone of Warcraft 2000
Official released source code for Warcraft 2000: Nuclear Epidemic, GSC Game World's 1998 RTS built to rival Warcraft II and StarCraft.
Platforms:Windows
Stars14
Updated3 years ago
LicenseUnknown
Release2023
Genre: Real-Time Strategy
Theme: Fantasy
Halted
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Original game imageClone of Crystalis
A reassemblable disassembly of the NES game Crystalis for ca65, about 92% complete on PRG-ROM and 88% on CHR-ROM, free to use uncredited.
Halted
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Original game imageClone of Star Raiders
A disassembly of Star Raiders' original 6502 assembly source, not a reimplementation; a work in progress and not yet playable.
Halted
Halted
Clone of Mega Man 7
Archived
Halted
Clone of Duke Nukem Forever
A mod project for Duke Nukem Forever (2011) adding a level/asset editor and aiming to fix up the base game, unaffiliated with Gearbox.
Halted
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Original game imageClone of Star Trek: Elite Force II
A maintenance update of the Star Trek: Elite Force II game source code, updated to compile under Visual Studio 2017 and on Linux.
Halted
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Original game imageClone of Star Control 2
The recovered original 3DO source code for Star Control 2, found in 2024 after the 2002 release used incomplete code.
Halted
Clone of Tread Marks
An unofficial Linux/OpenPandora SDL2 port of the open-sourced tank combat and racing game Tread Marks.
Halted
Original game image
Original game imageClone of Rex
An annotated, browsable disassembly of the ZX Spectrum version of Rex (1988), built with SkoolKit.
Halted
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Original game imageClone of Star Wars (1983 arcade game)
A remake of just the Death Star trench-run sequence from the 1983 Star Wars arcade game, built in CodeSkulptor.
Halted
Clone of Zarathrusta
A sci-fi multidirectional shooter about recovering stolen energy spheres, playable on Linux, Mac, Windows, or in a browser.
Platforms:WebWindowsLinux
Stars11
Updated6 years ago
LicenseGPL-3.0
Release2016
Genre: Action
Theme: Sci-Fi
Active
Clone of Xevious
A line-by-line 68K transcode of the arcade Xevious ROMs, targeting Neo Geo hardware and the AGA Amiga.
Halted
Original game image
Original game imageClone of SkyRoads
Active
Halted
Active
Original game image
Original game imageClone of Star Trek: Voyager – Elite Force
A native Android port of Star Trek: Voyager - Elite Force Holomatch with a Vulkan renderer and touch controls.
Sporadic
Sporadic
Clone of Uridium
A shared repository of Oric home-computer games, demos, tools and routines by many authors.
Active
Clone of Star Wars: Knights of the Old Republic
A native PlayStation Vita port of the Android release of KOTOR, loading your own game libraries with a so-loader.
Halted
Active
Original game image
Original game imageClone of Return to Castle Wolfenstein
A Return to Castle Wolfenstein source port based on iortcw, with a higher tick rate, Steam file detection and a CMake build.
Archived
Active
Clone of Star Wars Jedi Knight: Dark Forces II
A fork of OpenJKDF2 that ports the engine to the original Microsoft Xbox, using xquake's FakeGL renderer.
Stars8
Updated1 month ago
LicenseUnknown
Release2026
Genre: Fighting
Theme: Fantasy
Halted
Clone of Zarathrusta
The third Transball game, a Thrust-style, gravity-based game where you fly a ship to retrieve a sphere across 15 levels.
Platforms:WindowsLinuxOSX
Stars8
Updated6 years ago
LicenseGPL-2.0
Release2020
Genre: Action
Theme: Sci-Fi
Halted
Clone of Galaga
An SDL port of Joe Rumsey's X11 Galaga clone, originally released as shareware before going GPL.
Halted
Clone of Starshatter
The Starshatter space combat simulator's source code, migrated from Google Code and released under a BSD license.
Halted
Original game image
Original game imageClone of Alien Breed 3D
An Amiga build of John Girvin's Alien Breed 3D source, reviving the Chunky-Copper renderer for RTG output; currently unplayable.
Sporadic
Active
Original game image
Original game imageClone of X-COM: UFO Defense
A native port of OpenXcom Extended 8.6.1 to the New Nintendo 3DS, supporting UFO Defense and Terror From the Deep.
Sporadic
Clone of Super Star Trek
A Game Maker Studio remake of the Adventure Game Studio fan game Super Star Trek Meets 25th Anniversary.