Free & Open Source Sci-Fi Games
489 free, open-source sci-fi games — real clones and remakes you can download, inspect the source of, and modify.
Active
Clone of Doom
A community source port enhancing Ultimate DOOM, DOOM II, and DOOM 3, requiring a legally owned copy of DOOM 3 BFG Edition.
Halted
Sporadic
Halted
Clone of RimWorld
A RimWorld mod distributed as a Harmony-patched DLL, with separate builds maintained for each RimWorld version.
Platforms:WindowsLinuxOSX
Stars249
Updated1 year ago
LicenseMIT
Release2016
Genre: Simulation
Theme: Sci-Fi
Active
Archived
Halted
Sporadic
Clone of Doom
A pure Java source port of Doom, nearly complete but still missing network multiplayer.
Halted
Archived
Clone of Another World
rawgl is a re-implementation of Another World's game engine, supporting most original platform releases and data files.
Sporadic
Halted
Clone of Cave Story
A fork of NXEngine, the open-source Cave Story engine rewrite, ported to low-powered handhelds and phones.
Sporadic
Clone of Cave Story
CSE2 is a decompilation of Cave Story; this portable branch runs on Linux, macOS, Wii U, 3DS, and RISC OS in addition to Windows.
Sporadic
Halted
Clone of Flotilla
Flotilla is Brendon Chung's official 2010 source release, combining turn-based 3D ship combat with randomized exploration events.
Platforms:Windows
Stars185
Updated3 years ago
LicenseZlib
Release2020
Genre: Turn-Based Strategy
Theme: Sci-Fi
Halted
Sporadic
Clone of Otto Matic
An authorized update of Pangea Software's 2001 Otto Matic that runs on modern macOS, Windows and Linux.
Sporadic
Sporadic
Clone of Chasm: The Rift
A free SDL2 recreation of Chasm: The Rift that runs on the original game's data.
Sporadic
Active
Sporadic
Active
Sporadic
Clone of StarCraft
A StarCraft remake built on the open-source Stratagus engine, requiring an existing StarCraft install for game data.
Platforms:WindowsLinuxOSX
Stars156
Updated9 months ago
LicenseGPL-2.0
Release2015
Genre: Real-Time Strategy
Theme: Sci-Fi
Halted
Clone of Abuse
A fork of the Abuse SDL2 port adding OpenGL rendering, high-res images, cheat console, and Xbox 360 controller support for Windows.
Sporadic
Clone of Dune 2
A cross-platform enhancement of Dune II built on OpenDUNE, adding widescreen graphics, multiplayer for up to 6, and fan campaigns.
Platforms:WindowsLinux
Stars154
Updated8 months ago
LicenseGPL-2.0
Release2023
Genre: Real-Time Strategy
Theme: Sci-Fi
Active
Clone of MechCommander 2
An open-source reimplementation of MechCommander 2's closed engine, fixing bugs, with networking left unfinished.
Platforms:WindowsLinux
Stars154
Updated27 days ago
LicenseGPL-3.0
Release2016
Genre: Real-Time Tactics
Theme: Sci-Fi
Active
Clone of Star Wars: Knights of the Old Republic
A from-scratch reimplementation of the Odyssey engine used by both KotOR games, written in TypeScript and run via Electron or browser.
Halted
Halted
Clone of Elite
A Windows remake of Elite built with Allegro and DirectX, reaching Release 1.0 on 22 July 2001 after several betas.
Active
Clone of Outpost
A C++ redesign of Sierra's 1994 colony game Outpost, keeping its core concepts in a more responsive game.
Platforms:Windows
Stars143
Updated1 month ago
LicenseBSD-3-Clause
Release2018
Genre: Simulation
Theme: Sci-Fi
Halted
Clone of Strife
Night Dive Studios' 2020 GPL source release of Strife: Veteran Edition, the official remaster of 1996's Strife.
Platforms:WindowsLinuxOSX
Stars143
Updated4 years ago
LicenseGPL-2.0
Release2014
Genre: Action
Theme: Post-Apocalyptic
Halted
Halted
Halted
Clone of The Colony
The official Apache 2.0 source release of David A. Smith's 1988 Macintosh 3D adventure/shooter, with PC and Amiga ports.
Halted
Halted
Halted
Halted