Cloned Games

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
No preview
OGame Vue TS

Clone of OGame

A single-player browser space strategy game inspired by OGame, built with Vue 3 and TypeScript, with all data stored locally.
Platforms:Web
Stars516
Updated2 months ago
LicenseUnknown
Release2025
Genre: Turn-Based Strategy
Theme: Sci-Fi
Active
BBC Micro cassette Elite screenshot
BBC Micro cassette Elite

Clone of Elite

The cassette version of Ian Bell and David Braben's 1984 Elite source code, reformatted and documented by Mark Moxon, not reconstructed.
Platforms:BBC Micro
Stars487
Updated15 days ago
LicenseUnknown
Release2020
Genre: Action
Theme: Sci-Fi
Active
FreeSpace 2 Source Code Project screenshot
FreeSpace 2 Source Code Project

Clone of FreeSpace 2

FS2 Open, the FreeSpace 2 Source Code Project, is an open-source build of FreeSpace 2 targeting Windows, Linux, and macOS.
Platforms:WindowsLinuxOSX
Stars487
Updated11 days ago
LicenseUnknown
Release2013
Genre: Action
Theme: Sci-Fi
Active
Vange-rs screenshot
Vange-rs

Clone of Vangers

A Rust reimplementation of the Vangers engine using wgpu for native hardware-accelerated, and optionally voxel ray-traced, rendering.
Platforms:Web
Stars486
Updated11 days ago
LicenseApache-2.0
Release2016
Genre: Racing
Theme: Sci-Fi
Active
No preview
OpenOMF

Clone of One Must Fall: 2097

An open-source remake of the fighting game One Must Fall 2097 with modern networking across Windows, Linux and macOS.
Platforms:WindowsLinuxOSX
Stars478
Updated19 days ago
LicenseMIT
Release2013
Genre: Fighting
Theme: Sci-Fi
Sporadic
Nanosaur screenshot
Nanosaur

Clone of Nanosaur

Pangea's 1998 Mac game Nanosaur, updated with permission to run on modern macOS, Windows and Linux.
Platforms:WindowsLinuxOSX
Stars474
Updated5 months ago
LicenseUnknown
Release2020
Genre: TPS
Theme: Prehistoric
Active
Commodore 64 Elite screenshot
Commodore 64 Elite

Clone of Elite

The fully documented original Commodore 64 source code for Elite (1985), annotated line-by-line and built into four accurate variants.
Platforms:C64
Stars467
Updated11 days ago
LicenseUnknown
Release2024
Genre: Action
Theme: Sci-Fi
Active
Seed7 screenshot
Seed7

Clone of Star Trek

An open-source programming language whose example programs include recreations of classic games like Pac-Man and Tetris.
Platforms:Windows
Stars461
Updated12 days ago
LicenseGPL-2.0
Release2020
Genre: Simulation
Theme: Sci-Fi
Archived
No preview
Descent

Clone of Descent

Parallax Software's original 1998 Descent 1 source code, released without the sound and modem code the studio didn't own the rights to.
Platforms:WindowsOSXSaturn
Stars430
Updated8 years ago
LicenseUnknown
Release2012
Genre: FPS
Theme: Sci-Fi
Active
No preview
SR

Clone of Albion

A static recompiler that rebuilds classic DOS/Windows games like X-COM and Warcraft: Orcs & Humans as native modern builds.
Platforms:WindowsLinux
Stars416
Updated1 month ago
LicenseUnknown
Release2016
Genre: RPG
Theme: Sci-Fi
Active
NES Elite screenshot
NES Elite

Clone of Elite

Fully documented, hand-reconstructed source code for Elite on the NES that builds a working PAL or NTSC ROM.
Platforms:NES
Stars406
Updated15 days ago
LicenseUnknown
Release2023
Genre: Action
Theme: Sci-Fi
Halted
CCOSS screenshot
CCOSS

Clone of Cortex Command

CCOSS is the open-source release of Cortex Command's engine under AGPLv3, without game data, requiring the original game and Steam DLLs.
Platforms:Windows
Stars405
Updated2 years ago
LicenseAGPL-3.0
Release2019
Genre: Action
Theme: Sci-Fi
Halted
No preview
Return to Castle Wolfenstein Multiplayer

Clone of Return to Castle Wolfenstein

Official id Software GPL source release of Return to Castle Wolfenstein's multiplayer code; game data isn't included.
Platforms:Windows
Stars378
Updated14 years ago
LicenseGPL-3.0
Release2012
Genre: FPS
Theme: Sci-Fi
Active
No preview
BStone

Clone of Blake Stone: Planet Strike

BStone is an actively maintained source port of the Blake Stone series, adding high-res 3D rendering, texture upscaling, and 3D audio.
Platforms:WindowsLinuxOSX
Stars367
Updated1 month ago
LicenseUnknown
Release2013
Genre: FPS
Theme: Sci-Fi
Halted
Duke 2 Reconstructed screenshot
Duke 2 Reconstructed

Clone of Duke Nukem II

Duke 2 Reconstructed is a from-scratch reconstruction of Duke Nukem II's source code from disassembly, producing a byte-identical binary.
Platforms:DOS
Stars367
Updated1 year ago
LicenseGPL-2.0
Release2022
Genre: Platform
Theme: Sci-Fi
Active
No preview
Dune II - The Maker

Clone of Dune 2

Dune II - The Maker is an actively maintained Dune 2 remake built with CMake and GCC, with documented builds for Windows, Ubuntu, and macOS.
Platforms:WindowsLinuxOSX
Stars364
Updated11 days ago
LicenseUnknown
Release2012
Genre: Real-Time Strategy
Theme: Sci-Fi
Active
Vega Strike screenshot
Vega Strike

Clone of Elite

An open-source space trading and combat simulator with entirely original assets, inspired by the classic game Elite.
Platforms:Linux
Stars360
Updated11 days ago
LicenseUnknown
Release2015
Genre: Action
Theme: Sci-Fi
Halted
OpenSWE1R screenshot
OpenSWE1R

Clone of Star Wars Episode I: Racer

A partial open-source port of Star Wars Episode I: Racer that uses CPU emulation to run the original game cross-platform.
Platforms:Windows
Stars347
Updated6 years ago
LicenseGPL-2.0
Release2017
Genre: Racing
Theme: Sci-Fi
Sporadic
FTE QuakeWorld screenshot
FTE QuakeWorld

Clone of Quake 2

FTEQW is an advanced, portable open-source engine for idTech games like Quake, Quake II, and III, with servers holding hundreds of players.
Platforms:WindowsLinux
Stars341
Updated3 months ago
LicenseGPL-2.0
Release2021
Genre: FPS
Theme: Sci-Fi
Halted
No preview
Doom Classic for iOS

Clone of Doom

id Software's free GPL source-code release of DOOM Classic for iOS, not including any game data, which remains under the original EULA.
Platforms:iOS
Stars339
Updated10 years ago
LicenseGPL-2.0
Release2014
Genre: FPS
Theme: Sci-Fi
Active
Quadrilateral Cowboy screenshot
Quadrilateral Cowboy

Clone of Quadrilateral Cowboy

Blendo Games' official GPL source release for Quadrilateral Cowboy, a first-person cyberpunk hacking adventure built on idTech4.
Platforms:Windows
Stars331
Updated1 month ago
LicenseGPL-3.0
Release2020
Genre: Adventure
Theme: Cyberpunk
Active
No preview
Woof!

Clone of Doom

A modern continuation of Lee Killough's MBF Doom source port, adding widescreen rendering, uncapped framerate, and gamepad support.
Platforms:WindowsLinux
Stars326
Updated11 days ago
LicenseGPL-2.0
Release2016
Genre: FPS
Theme: Sci-Fi
Active
Open Imperium Galactica screenshot
Open Imperium Galactica

Clone of Imperium Galactica

A Java reimplementation of the 4X space strategy game Imperium Galactica, bundling its data with Digital Reality's permission.
Platforms:WindowsLinuxOSX
Stars325
Updated1 month ago
LicenseLGPL-3.0
Release2015
Genre: Strategy
Theme: Sci-Fi
Halted
Project Porcupine screenshot
Project Porcupine

Clone of RimWorld

A Unity tutorial project and base-building game skeleton inspired by Dwarf Fortress and RimWorld.
Platforms:WindowsLinuxOSX
Stars325
Updated1 year ago
LicenseGPL-3.0
Release2017
Genre: Simulation
Theme: Sci-Fi
Active
CCCP screenshot
CCCP

Clone of Cortex Command

CCCP is a community-driven continuation of Cortex Command's development, free and open source under AGPLv3, with an active mod portal.
Platforms:WindowsLinuxOSX
Stars322
Updated1 month ago
LicenseAGPL-3.0
Release2024
Genre: Action
Theme: Sci-Fi
Sporadic
FreeHL screenshot
FreeHL

Clone of Half-Life

A QuakeC reimplementation of Half-Life via the Nuclide SDK on the FTE Engine, semi-playable across Windows, macOS, and Linux.
Platforms:WindowsLinuxOSX
Stars320
Updated10 months ago
LicenseISC
Release2021
Genre: FPS
Theme: Sci-Fi
Sporadic
Doomsday Engine screenshot
Doomsday Engine

Clone of Doom

A portable, enhanced source port supporting Doom I/II, Heretic, and Hexen, built as cross-platform C++ libraries.
Platforms:WindowsLinuxOSX
Stars303
Updated3 months ago
LicenseUnknown
Release2011
Genre: FPS
Theme: Sci-Fi
Archived
PrBoom+ screenshot
PrBoom+

Clone of Doom

Platforms:WindowsLinuxOSX
Stars301
Updated3 years ago
LicenseGPL2*
Release2017
Genre: FPS
Theme: Sci-Fi
Sporadic
GBADoom screenshot
GBADoom

Clone of Doom

A Game Boy Advance port of prBoom supporting Doom's IWADs, with variable framerate and no multiplayer or demo support.
Platforms:GBA
Stars297
Updated1 year ago
LicenseUnknown
Release2019
Genre: FPS
Theme: Sci-Fi
Active
No preview
Odamex

Clone of Doom

A client/server Doom source port for Internet multiplayer with up to 255 players and many competitive game modes.
Platforms:WindowsLinuxOSX
Stars294
Updated11 days ago
LicenseGPL-2.0
Release2015
Genre: FPS
Theme: Sci-Fi
Halted
No preview
War Worlds

Clone of War Worlds

The open-source release of War Worlds, a multiplayer space strategy game whose live service shut down in 2014.
Platforms:Android
Stars292
Updated2 years ago
LicenseMIT
Release2013
Genre: Simulation
Theme: Sci-Fi
Active
Space Station 3D screenshot
Space Station 3D

Clone of Space Station 13

An open-source, pre-alpha 3D revival of Space Station 13, built in Unity and expanding *beep's original SS3D demo.
Platforms:Windows
Stars291
Updated1 month ago
LicenseUnknown
Release2019
Genre: RPG
Theme: Sci-Fi
Halted
AdaDoom3 screenshot
AdaDoom3

Clone of Doom 3

An attempt to re-engineer id Tech 4, the Doom 3 engine, in the Ada language; mostly incomplete with development halted.
Platforms:None
Stars288
Updated3 years ago
LicenseUnknown
Release2013
Genre: FPS
Theme: Sci-Fi
Active
No preview
NES Games Disassembly

Clone of RoboCop

Compilable, editable disassemblies of 26 NES games that rebuild ROMs identical to the originals.
Platforms:NES
Stars282
Updated1 month ago
LicenseUnknown
Release2021
Genre: Action
Theme: Sci-Fi
Sporadic
Spearmint screenshot
Spearmint

Clone of Quake 3

An id Tech 3 engine fork supporting Quake III Arena and Team Arena, with partial Wolfenstein support in progress.
Platforms:WindowsLinuxOSX
Stars277
Updated4 months ago
LicenseGPL-3.0
Release2013
Genre: FPS
Theme: Sci-Fi
Sporadic
Doom64EX screenshot
Doom64EX

Clone of Doom 64

A reverse-engineering project recreating Doom 64 with added modding features, built in C++ and SDL2 for Linux, Windows, and macOS.
Platforms:N64
Stars273
Updated10 months ago
LicenseGPL-2.0
Release2014
Genre: FPS
Theme: Sci-Fi
Halted
No preview
Natural Selection

Clone of Natural Selection

The official GPL source release of Natural Selection, the Half-Life mod by Unknown Worlds.
Platforms:Windows
Stars273
Updated12 years ago
LicenseUnknown
Release2014
Genre: FPS
Theme: Sci-Fi
Sporadic
No preview
Duke Nukem Zero Hour N64

Clone of Duke Nukem: Zero Hour

A decompilation of Duke Nukem: Zero Hour for the Nintendo 64, buildable into US and French ROMs via a Splat-based toolchain.
Platforms:N64
Stars271
Updated10 months ago
LicenseUnknown
Release2022
Genre: TPS
Theme: Sci-Fi
Active
No preview
The Eternity Engine

Clone of Doom

An advanced Doom-engine source port descended from SMMU, built with SDL2 and actively maintained across major platforms.
Platforms:WindowsOSX
Stars268
Updated19 days ago
LicenseGPL-3.0
Release2014
Genre: FPS
Theme: Sci-Fi

Browse all themes

We’d like to use analytics cookies to understand how visitors use this site. See our Privacy Policy for details. Nothing else is tracked, and the site works the same either way.