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 Earth 2140
A work-in-progress OpenRA-based remake of the 1997 RTS Earth 2140, now in multiplayer alpha.
Platforms:WindowsLinuxOSX
Stars71
Updated1 month ago
LicenseGPL-3.0
Release2022
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Archived
Clone of Another World
An archived JavaScript/HTML5 reimplementation of Another World that interprets the original game's own bytecode, with a rewind feature.
Active
Clone of Unreal Tournament
An unofficial Android port of Unreal Tournament, controller-first, needing your own v1.400 game files.
Halted
Clone of Machines: Wired for War
Official GL-ported source code release of Machines: Wired For War, a 3D RTS, published with permission from Night Dive Studios.
Platforms:WindowsLinux
Stars68
Updated4 years ago
LicenseGPL-3.0
Release2020
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Clone of Marathon
A port of the AlephOne engine to Android for playing the Marathon saga, with one APK per chapter.
Halted
Clone of Good Robot
This is the official source code for Good Robot, a procedurally generated shoot-'em-up with light RPG elements by Pyrodactyl Games.
Platforms:WindowsLinuxOSX
Stars66
Updated6 years ago
LicenseMIT
Release2020
Genre: Shooter
Theme: Post-Apocalyptic
Archived
Original game image
Original game imagePlatforms:Windows
Stars66
Updated11 years ago
LicenseUnknown
Release2015
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Clone of Another World
Another World Suite is a Rust implementation of the Another World game engine, compiled to WebAssembly to run in a browser.
Archived
Original game image
Original game imageClone of Heavy Metal: F.A.K.K. 2
This is the official released source code for Heavy Metal: F.A.K.K. 2, not a third-party remake; the project is archived.
Halted
Original game image
Original game imageClone of Total Annihilation
A real-3D OpenGL reimplementation of Total Annihilation, requiring the original game's resource files.
Platforms:WindowsLinuxOSX
Stars64
Updated4 years ago
LicenseGPL-2.0
Release2017
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Clone of Steins;Gate
libnpengine is a free reimplementation of the Nitroplus visual novel engine for Linux, currently able to run Steins;Gate and others.
Halted
Clone of Alien 3
This repository preserves Michael J Archer's complete 6502 assembly source code for the Commodore 64 version of Alien 3.
Halted
Original game image
Original game imageClone of Dune 2
This is a Java implementation of a real-time strategy game, built with the slick2d-maven framework, requiring Maven and Java 1.8.
Active
Archived
Original game image
Original game imageClone of Blood II: The Chosen
This repository contains the officially released LithTech-engine source code for Blood II: The Chosen, released by Monolith.
Halted
Original game image
Original game imageClone of SiN
Night Dive Studios' official source release of SiN Gold, the 1998 Ritual Entertainment shooter built on a modified Quake II engine.
Archived
Original game image
Original game imageClone of Star Raiders
A hand-typed transcription of the original Atari 800 Star Raiders source code, made from scanned printed listings.
Active
Halted
Active
Original game image
Original game imageClone of Star Wars Episode I: Racer
A partial decompilation of Star Wars Episode 1 Racer that re-implements game functions to support modding and an HD replacement mod.
Sporadic
Original game image
Original game imageClone of Return to Castle Wolfenstein
A PS Vita port of id Software's open-source Return to Castle Wolfenstein single-player release.
Active
Original game image
Original game imageClone of Alien Breed 3D II: The Killing Grounds
An actively maintained rebuild of the Alien Breed 3D II: The Killing Grounds engine, compatible with original game data or mods.
Active
Sporadic
Clone of Star Trek: Voyager – Elite Force
An open-source engine reimplementation of Star Trek: Voyager - Elite Force's Holomatch mode, built on the ioquake3-derived ioEF engine.
Halted
Original game image
Original game imageClone of Pararena
Source code of Pararena, John Calhoun's commercial Macintosh game published by Casady & Greene.
Halted
Original game image
Original game imageClone of StarCraft
Stratagus is a free fantasy real-time strategy game engine, and its README lists the game packages built on it, Wargus, War1gus and Stargus.
Stars56
Updated4 years ago
LicenseGPL-2.0
Release2011
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Original game image
Original game imageClone of Descent
A source port of the DOS game Descent to Android and iOS; requires game files from a licensed copy.
Halted
Original game image
Original game imageClone of Star Dust
A reverse-engineered ZX Spectrum source reconstruction of the 1987 game Stardust, made by its original developers.
Halted
Original game image
Original game imageClone of MechCommander 2
A patched version of MechCommander 2's Microsoft-released source code, though the README doesn't detail what the patches change.
Platforms:Windows
Stars54
Updated3 years ago
LicenseBSD-2-Clause
Release2014
Genre: Real-Time Tactics
Theme: Sci-Fi
Active
Clone of Elite
Source code for the disc version of Elite on the BBC Micro, reconstructed from a disassembly and documented line-by-line by Mark Moxon.
Halted
Clone of Delta
A self-described 'weekend homage' to the C64 shoot-em-up Delta, built in JavaScript and CSS, deliberately left unfinished.
Halted
Original game image
Original game imageClone of Mega Man 3
A finished disassembly of the NES game Mega Man 3 (NTSC-U) that assembles to a clean ROM.
HaltedOriginal game image
Original game imageClone of Mega Man 3
A complete disassembly of the NTSC-U Mega Man 3 NES ROM, covering all code and data, reassembling byte-for-byte via the xkas-plus build.
Halted
Active
Clone of Star Fox 64
A Star Fox 64 port for the Sega Dreamcast, based on a decompilation; you build it from your own N64 ROM.
Stars47
Updated2 months ago
LicenseCC0-1.0
Release2025
Genre: Shooter
Theme: Sci-Fi
Halted
Halted
Clone of Radix: Beyond the Void
RAD is a from-scratch engine recreation of the 1995 DOS shooter Radix: Beyond the Void with OpenGL rendering.
