Open-source alternatives to DevilutionX

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

tModLoader is a modding framework and toolset designed for expanding game content and extending core game logic. It provides a polymorphic content API that allows for the creation of new items, NPCs, projectiles, and world assets through object-oriented inheritance. The project is distinguished by its advanced code modification capabilities, utilizing intermediate language bytecode patching and reflection-based private access to alter internal game behavior. It features a hot-reloading assembly runtime that enables developers to recompile and apply source code changes in real-time without res

This project is a reverse-engineered game port and reimplementation of a classic title designed to run natively on modern hardware. It utilizes a custom game engine that recreates original machine code logic and uses extracted assets to provide a playable experience. The implementation ensures behavioral parity through frame-perfect logic verification, comparing real-time execution against reference logs. It distinguishes itself with a multi-language localization system that extracts dialogue and fonts from regional files, as well as visual enhancements including pixel shaders, widescreen asp

This repository is a comprehensive collection of functional 2D and 3D demo projects and implementation samples for the Godot Game Engine. It serves as an interactive tutorial and reference library, providing a working codebase to demonstrate how to apply engine features in real-world scenarios. The collection focuses on practical implementation guides, covering a wide array of technical capabilities from basic engine fundamentals to advanced rendering and scripting techniques. It allows users to study the application of node-based composition, asset pipelines, and game logic through direct ex

Space Station 14 is a C# multiplayer game and roleplay simulation framework. It is built upon an Entity-Component-System (ECS) game engine that separates logic into systems and data into components to manage complex entity interactions. The project functions as a grid-based physics simulator with a YAML data-driven prototype system for defining game objects. The project features a specialized 2D sprite rendering engine that maps server-side appearance data to client-side shaders. It implements a networking model with client-side prediction and dirty-flagged state synchronization to reduce inp

Endless Sky is an open-source space trading simulation, 2D space combat simulator, and narrative exploration game. It functions as a plugin-based game engine that allows users to explore a vast universe, engage in tactical ship battles, and progress through a central plot within a sandbox environment. The project is distinguished by its highly moddable architecture, utilizing a directory-based plugin system and data-driven entity definitions to allow for content extensions and behavior overrides without recompiling source code. It further supports visual customization through programmable ver

Dusklight is a suite of specialized toolkits designed for legacy game porting and engine reimplementation. It provides a framework for recreating legacy game environments through reverse engineering to ensure behavioral accuracy and stability on modern hardware. The project features a cross-platform graphics renderer that uses modern graphics APIs to display 2D and 3D content across different operating systems. It includes an application configuration toolkit that allows for the modification of software appearance and behavior through custom theming and experience customization. The system i

Ambient is a cross-platform multiplayer game engine and runtime environment developed in Rust. It provides a system for building and deploying high-performance games that run across web browsers and desktop platforms using WebAssembly and WebGPU. The project features a networked database that automatically replicates real-time state and components between servers and players. It utilizes WebAssembly sandboxes to isolate game logic, which prevents individual script crashes and allows for the secure execution of untrusted code. The framework includes a graphics system for high-fidelity 3D visu

OpenLara is an open-source game engine and classic game emulator designed to load and execute original game data files from classic action-adventure titles. It functions as a cross-platform game runtime that enables legacy game assets to run on modern hardware and operating systems. The engine features a deterministic physics system using fixed-point coordinate math to ensure consistent movement and behavior across different hardware environments. The project incorporates a component-based entity system and a data-driven level loading process to reconstruct world geometry and object placemen

Spring is a cross-platform game engine and framework designed specifically for the development and execution of multiplayer real-time strategy games. It provides a high-performance simulation environment for managing large-scale battles and unit movements across different operating systems using a shared codebase. The engine functions as a multiplayer game server and networking layer, coordinating real-time game state and match synchronization between remote players. It includes a dedicated lobby client system for multiplayer match coordination as well as the capability to execute single-play

Zelda64Recomp is a native game recompilation project that translates legacy binary machine code into modern machine code. It functions as a native hardware port and a static recompiled binary, executing original game logic directly on modern CPUs and GPUs to run without an emulator. The project serves as a moddable game engine, providing a framework to apply community texture packs and code patches to the recompiled title. It includes native hardware porting capabilities that remove emulator overhead to improve stability and frame rate control. The software covers retro game modernization th

Untrusted is a web-based programming puzzle and meta-programming game where progress is achieved by rewriting the active JavaScript source code while the application is running. It functions as a code-editing adventure game that combines programming education with puzzle gameplay. The experience centers on real-time logic modification, requiring players to edit scripts to change environmental rules, manipulate game behavior, and resolve puzzle-based objectives. This interactive code editing allows players to overwrite active functions and variables to overcome obstacles. The project includes

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

Source Engine is a cross-platform game engine designed for the development and execution of interactive three-dimensional applications. It provides a framework for rendering complex environments and managing multiplayer networking, functioning as a middleware solution for hosting independent game servers. The engine distinguishes itself through a client-server authoritative networking model that enables direct player connectivity without reliance on external authentication or matchmaking services. It utilizes a data-driven asset pipeline and a component-based entity system to decouple engine

Shipwright is a native execution engine designed to run decompiled legacy game code on modern hardware. It functions as a game engine execution layer that provides a high-performance environment for legacy logic while ensuring compatibility with current systems. The project features a pluggable graphics API wrapper that allows for switching between different rendering backends to ensure visual stability across various operating systems. It also includes a custom asset loader that imports external archive files to modify game content and add custom assets. Additional capabilities include an i

OpenTTD is an open-source game engine and transport simulation game. It provides an isometric sandbox environment for building and managing complex logistics and transport networks. The project functions as a multiplayer simulation sandbox where users can build infrastructure cooperatively or competitively in a shared virtual world. The platform is designed as a moddable simulation system that supports external assets, graphics, and gameplay modifications. It includes mechanisms for downloading and integrating add-on content and utilizes a plugin-based system to extend game mechanics beyond t

OpenRA is an open-source game engine designed for the development and modernization of real-time strategy titles. It provides a modular framework that allows developers to build standalone games or total conversion modifications by leveraging a trait-based entity composition system. The engine is built to support both the preservation of classic strategy games and the creation of new experiences, offering cross-platform compatibility and a flexible architecture for defining game rules and unit behaviors. The engine distinguishes itself through a configuration-driven approach where game logic,

ARCHIVED Modern reimplementation of the Diablo 1 game engine

A somewhat upgraded/refactored version of NXEngine by Caitlin Shaw.

Abyss Engine clean-room reimplementation of Diablo 2, written in C. The goal is to recreate the original game engine, but on a portable platform that can also easily be modded and extended.

This project is an open-source 3D kart racing game and engine. It functions as a multi-mode competitive racer and customizable racing simulator featuring physics-based driving and vehicle collisions across diverse environments. The software includes tools for designing custom karts, authoring racing challenges, and creating 3D tracks. It supports a variety of competition styles beyond traditional racing, including soccer matches and scavenger hunts, and features a tactical combat powerup system and multiple kart classes with distinct performance attributes. The engine provides capabilities f

The Powder Toy is a C++ physics engine and material simulation software that operates as a falling sand physics sandbox. It provides a simulation environment where solids, liquids, and gases interact based on heat, pressure, and velocity. The project is a scriptable sandbox environment, offering an external scripting interface and behavioral scripting to modify game mechanics, automate tasks, and define custom simulation logic. The software supports the construction of complex machinery, physical structures, and functional logic circuits through simulated electronic components and sensors. I

Supertux is an open-source 2D platforming game and game engine. It features a side-scrolling adventure where players navigate themed worlds and defeat enemies to reach specific goals. The project is designed for cross-platform availability, providing a consistent experience across desktop, Android devices, and web browsers. The browser version utilizes WebAssembly to allow immediate playback without local software installation. The software includes an integrated level editor and tools for custom level design, enabling the creation of unique game environments. Other capabilities include inpu

noVNC is an HTML5 remote desktop viewer and VNC web client that allows users to access and control remote desktops, virtual machines, and containers through a web browser. It functions as a remote desktop management tool that integrates the VNC protocol to enable remote server administration without the need for a dedicated client application. The project includes a VNC WebSocket proxy that translates binary VNC network traffic into WebSockets to bypass browser restrictions on direct TCP connections. This proxy service supports bridging connections to multiple remote servers by listening on v

Bazzite is an immutable, atomic-image-based operating system designed for gaming performance and handheld hardware. It utilizes a read-only root filesystem and versioned images to provide atomic updates and instant system rollbacks, ensuring a stable core environment. The system is distinguished by its deep optimization for portable gaming devices, featuring dedicated handheld hardware management for CPU undervolting, fan control, and display refresh rate overclocking. It includes a specialized gaming mode that boots directly into a console-like interface with integrated input mapping and a t

This project is an open-source, cross-platform rhythm game engine designed to execute musical gameplay by synchronizing visual hit objects with audio tracks. It functions as a comprehensive competitive gaming platform that tracks player performance metrics, manages official leaderboards, and facilitates the distribution of rhythm-based challenges across desktop and mobile operating systems. The engine distinguishes itself through a modular architecture that decouples core gameplay logic from the engine, allowing developers to implement distinct game modes as swappable rulesets. It includes a

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