Open-source alternatives to Endless Sky

Mindustry is a cross-platform game engine and factory automation simulation that combines resource management with tower defense strategy. Players construct complex supply chains and automated networks to process materials while building defensive structures to protect a core from waves of hostile mechanical forces. The project utilizes a deterministic lockstep networking model to ensure simulation consistency across desktop and mobile devices. It is built on an entity-component-system architecture and a tile-based grid simulation, allowing for the efficient management of thousands of active

OpenDiablo2 is an open-source re-implementation of an isometric action role-playing game engine. It functions as a cross-platform game client designed to execute core mechanics and logic across multiple operating systems using external game assets. The project focuses on recreating the functionality of a classic action RPG from the ground up through a community-driven effort. It provides a framework for running a game engine that simulates specific gameplay experiences and movement patterns. The engine includes capabilities for isometric projection rendering, deterministic game state simulat

OpenRCT2 is an open-source reimplementation of a classic amusement park management simulation engine. It functions as a cross-platform engine that modernizes the original game, enabling it to run on contemporary operating systems while maintaining full compatibility with legacy assets and data files. The project distinguishes itself by providing a comprehensive multiplayer simulation server that supports cooperative, real-time park management and construction across multiple connected clients. It utilizes a deterministic lockstep networking model and a centralized action-based validation syst

BepInEx is a Unity game modding framework that enables the injection of custom C# code and external assemblies into running processes without modifying original binaries. It provides a plugin loader and a dependency resolution engine to ensure that external modules are initialized in the correct order based on defined metadata requirements. The framework includes a centralized plugin configuration system for storing and editing custom settings via files and interactive inputs. It also features a runtime object inspector for browsing and debugging active game objects and components within a Un

Bloxstrap is a custom game bootstrapper and configuration tool for Roblox. It replaces the standard launcher to enable advanced startup configurations, inject internal engine flags, and manage a specialized installation directory. The project provides a client mod manager that allows users to override local assets, such as sounds, textures, and fonts, and ensures these customizations persist across game updates. It includes a configuration utility to unlock hidden graphics settings and engine parameters, alongside a server tracker that identifies the geographic location of active game servers

The Source Engine SDK is a C++ game development kit and modding framework designed for creating game modifications and custom gameplay extensions for the Source engine. It provides a structured environment and a collection of source code and binaries required to build custom content for compatible titles. The kit serves as a toolset for C++ game engine programming, enabling the development of custom gameplay mechanics, new rulesets, and game modes. It includes the libraries and headers necessary to compile and build gameplay extensions and custom game content.

MelonLoader is a game engine plugin loader designed to inject custom code and load external plugins into Unity games. It functions as a modding framework that supports both Mono and Il2Cpp runtimes, allowing for the modification of games across different backend architectures. The project enables the patching and hooking of functions within Unity games, specifically providing a system for managing C# assemblies in Mono environments and a framework for patching the Interop C++ backend used by Il2Cpp. The system handles the interception of the application boot process to load third-party mods

vcmi is an open-source game engine for Heroes of Might and Magic III that recreates the gameplay, logic, and rendering of the original strategy game. It serves as a cross-platform game runtime supporting Windows, Linux, macOS, Android, and iOS, providing a turn-based strategy simulator for strategic world map navigation and tactical combat. The project is built as a moddable game framework, featuring a data-driven modding system and a sandboxed Lua scripting integration. These allow for the definition of custom gameplay logic, spell effects, and the addition of new factions, characters, and a

This project is a real-time strategy game and military combat simulator focused on modern warfare. It provides a simulation where players build bases and command military units to achieve tactical objectives and execute combat operations across various global locations. The software functions as a user-generated content platform, featuring a community workshop for creating, uploading, and sharing custom maps. It also includes a narrative-driven single-player campaign consisting of a series of strategic missions. Gameplay involves battling computer-controlled commanders that utilize distinct

devilutionX is an open-source, cross-platform reimplementation of the original Diablo 1 game engine. It is a software framework designed to run the original action RPG logic and mechanics on modern operating systems by rewriting the engine in a current programming language. The project modernizes the legacy experience by adding support for widescreen resolutions, high-definition scaling, and configurable input mapping for various hardware controllers. It also introduces quality-of-life enhancements such as health bars, auto-loot, and tools to modify game speed and combat rules. The engine co

Luanti is an open-source sandbox game engine designed for the creation and exploration of interactive three-dimensional voxel environments. It functions as a platform for building persistent digital spaces where users can modify block-based worlds and share custom content. The engine provides a framework for multiplayer interaction, utilizing a client-server architecture to synchronize world states across connected participants. It incorporates a scripting interface that allows for the integration of user-created modifications, alongside a centralized distribution system for managing and inst

Inkos is an automated fiction pipeline and interactive narrative engine designed for generating novels, scripts, and interactive games. It employs a multi-stage writing workflow that manages long-form narrative memory through a database-backed system to prevent context drift and maintain character and world consistency. The system distinguishes itself through a style-fingerprinting engine that extracts linguistic patterns from reference texts to mimic specific authorial voices and refine AI prose. It utilizes a role-based model routing system to assign different language models to specific ta

Minetest is an open-source voxel game engine and platform used to create and share moddable 3D block-based games. It provides a framework for building interactive grid environments and generating custom voxel worlds. The project features a Lua-based modding framework that allows for the extension of game behavior and the addition of custom content without altering the core engine. This data-driven system supports a dedicated workflow for modifying game environments and logic. The engine supports multiplayer game hosting through a dedicated server architecture, enabling multiple players to co

Murder is an entity component system game engine designed for 2D game development. It provides a core framework for managing game objects through an ECS architecture and includes a dedicated 2D game editor for asset management and real-time property configuration. The engine features a specialized 2D rendering pipeline supporting pixel art, sprite slicing, and parallax effects. It includes a hierarchical A* pathfinding system for agent navigation and a comprehensive asset management system for serializing and loading game resources. The project covers a broad range of capabilities, including

Openage is an open-source game engine designed to execute real-time strategy games. It provides the core logic, networking, and rendering infrastructure necessary to recreate classic strategy mechanics across multiple operating systems. The engine utilizes a deterministic lockstep simulation and a client-server architecture to maintain synchronized game states across participants. It distinguishes itself through a data-driven configuration system that allows for extensive game modding, enabling users to adjust mechanics and visual elements by editing human-readable files without requiring sou

This project is a programming education resource and a collection of vintage game ports. It provides a library of classic computer game implementations and algorithmic problems translated into modern memory-safe scripting languages for educational study and execution. The collection focuses on the implementation of game logic and the practice of fundamental computer science algorithms. It includes diverse examples of procedural content generation, such as random mazes and text-based art, alongside mathematical visualizations. The project covers a wide array of simulation categories, includin

shapez.io is an open-source automation base building game and infinite sandbox factory simulation. Players extract and process geometric shapes through conveyor belts and industrial automation to meet delivery goals within an endless map. The project incorporates a logic circuit simulation environment, allowing for the creation of automated control systems using wiring and logic gates to optimize factory operations. It utilizes an entity-component game architecture to manage thousands of active elements across its simulation. Gameplay covers industrial automation and resource logistics, spec

This project is a curated, community-driven repository that serves as a centralized knowledge base for open-source game development. It provides a structured directory of high-quality links, project references, and learning materials designed to assist developers in discovering tools, libraries, and functional game examples. The collection is maintained through decentralized peer review, allowing contributors to expand the resource list via pull requests. By organizing content into a hierarchical taxonomy, the repository enables users to evaluate different technology stacks, study implementat

This repository provides the source code for the Unity game engine, serving as a reference for the internal implementation of its core systems and managed scripting environment. It functions as a development resource for understanding how high-level C# logic interacts with the underlying engine architecture to build interactive 2D and 3D applications. By providing visibility into the engine's source files, this project enables developers to inspect execution flows and trace implementation details. This transparency supports the troubleshooting of complex behaviors and the analysis of how spec

Small is a cross-platform plugin framework and modularization tool designed to break monolithic mobile applications into independent components. It provides a modular mobile architecture that allows developers to split applications into decoupled plugins to reduce system complexity and memory usage across multiple operating systems. The framework includes a dynamic module loader for on-demand feature loading to improve startup times and a dependency injection service registry that connects feature modules to a central core for service discovery. The system provides a platform abstraction lay

MagicMirror is an open source framework for creating personalized information dashboards, specifically designed for use as a modular smart mirror platform and a plugin-based dashboard framework. It functions as a system for aggregating data feeds and modular components to create a centralized information hub. The platform utilizes a module-based plugin architecture that allows for the development and integration of custom third-party plugins through a standardized interface. This extensibility enables the creation of personalized displays and custom data widgets. The system supports a headle

Hapi is a configuration-driven web framework for building secure and scalable HTTP servers and APIs on the Node.js runtime. It functions as a REST API development framework and an enterprise server implementation focused on stability, security, and comprehensive input validation. The framework is built around a plugin-based architecture, allowing core functionality and custom logic to be organized into modular, registerable plugins. It serves as an HTTP request lifecycle manager, enabling the interception and modification of requests through pre-handlers and extensions before they reach the f

CyberEngineTweaks is a modding framework for Cyberpunk 2077 that provides a suite of tools for engine patching, scripting extensions, and the creation of interactive in-game modification interfaces. It functions as a scripting engine extension and patching tool designed to modify engine behavior and add custom game logic. The project distinguishes itself by combining a script-injection framework with a graphical user interface library, allowing for the development of custom settings menus and overlays directly within the game engine. It enables low-level engine modifications to improve perfor

Vorpal is a Node.js interactive CLI framework and terminal user interface library used to build extensible command-line shells. It functions as an interactive command-line parser that converts string input into executable functions, managing the lifecycle of terminal sessions and command routing. The framework is distinguished by a plugin-based extension architecture that allows external modules to register new commands, shared behaviors, and complete command suites into the core environment. It supports the creation of custom shell environments with specialized namespaces and a system for pe

DataX is a distributed data integration framework and plugin-based ETL tool designed for synchronizing large datasets between heterogeneous sources and destinations. It functions as a JDBC data migration engine and offline synchronization tool, enabling the movement of data between relational databases, NoSQL stores, and object storage. The system utilizes a plugin-based connector architecture that decouples reader and writer logic, allowing it to map and transform data types across different storage engines using a standardized internal representation. This design supports heterogeneous data

Piccolo is a mini game engine designed for building small-scale games with cross-platform support. It compiles and runs on Windows, macOS, and Linux from a unified codebase, and includes an editor integration for live editing and debugging. The engine uses a component-based entity system with data-oriented design, storing component data in contiguous arrays for cache-friendly iteration. It features a fixed timestep game loop that decouples simulation updates from rendering frame rate, and provides a physics debug overlay that renders visual shapes from simulation data synchronized with the ed

This project is a C-based multimedia toolkit and cross-platform game framework designed for building interactive applications. It provides a low-level programming interface that grants direct access to hardware-accelerated graphics, real-time audio processing, and user input handling. By utilizing an immediate-mode rendering architecture, the library processes visual state changes frame-by-frame, which simplifies the logic required for dynamic interfaces and interactive simulations. The library distinguishes itself through a zero-dependency design that avoids complex external build requiremen