LittleJS is a fast, lightweight, and fully open source HTML5 game engine designed for simplicity and performance. Its small footprint is packed with a comprehensive feature set including 2D and 3D rendering, physics, particles, sound, and input handling. The code is very clean and well documented with many examples to get you started quickly.

A web-first game engine

Crown is a complete and cross-platform game engine designed for flexibility, performance, and fast-iterations.

Blazium Engine is a free, open-source fork of Godot for building cross-platform 2D and 3D games and applications, with the tools, platform integrations, and improvements you need.

Modoki is a TypeScript game engine and Unity-style visual editor for 2D, 2.5D and 3D mobile games. What makes it different is that it's built for AI agents. Through an MCP server, an agent like Claude Code can do almost everything a human can in the editor. It can read the live game world, edit scenes and prefabs, press Play, run builds, and check its own work with live data and rendered frames.

Gideros is a cross-platform development environment for creating games and interactive applications in 2D or 3D. It is easy to pick up, quick to develop and robust to deploy.

A powerful, beautiful, simple, and open web rendering engine

Butano is a modern C++ high level engine for the Game Boy Advance.

A powerful and intuitive toolkit that allows Blender, 3ds Max, or Maya artists to create immersive web-based experiences

An open source HTML5 game engine that empowers developers and designers to focus on content

s&box is a spiritual successor to Garry’s Mod, using Source 2 to create a modern, intuitive, moddable game development environment.

Usagi is a 2D game engine for making pixel art games in Lua 5.5. It features live reload, single-command cross-platform export, and a pause menu with input remapping built in.

A free game engine written in TypeScript for making 2D games in HTML5 canvas, whether you're new to game development or you're an experienced game developer.

Fast and lightweight 2D JavaScript library that allows everyone to enjoy the power of hardware acceleration without prior knowledge of WebGL

An engine designed for development teams (C++/C# programmers, 3D artists) working on interactive 3D apps

A refreshingly simple data-driven game engine built in Rust

A no-code, open-source, free, and easy 2D/3D game-making app

A game engine for high-performance cross-platform games

A free and open source fantasy computer for making, playing and sharing tiny games

A dead simple 2D game engine for Go

A custom-made game engine based on the Raylib Framework. The Main focus is being performant and only using draw functions instead of textures. When using Shape Engine everything from Raylib is available as well.

Simple DirectMedia Layer is a cross-platform development library designed to provide low level access to audio, keyboard, mouse, joystick, and graphics hardware via OpenGL and Direct3D. It is used by video playback software, emulators, and popular games including Valve's award winning catalog and many Humble Bundle games.

FNA is a reimplementation of the Microsoft XNA Game Studio 4.0 Refresh libraries

Prowl is an open-source, MIT-licensed game engine developed in pure C# in latest .NET. It aims to provide a seamless transition for developers familiar with Unity by maintaining a similar API while also following KISS and staying as small and customizable as possible. Ideally, Unity projects can port over with as little resistance as possible.

Redot Engine is an open source fork of Godot with the goal of fulfilling the promise of Godot.

Ceramic is a cross-platform framework that lets you create 2D apps and games written in the Haxe programming language. It can export your app natively to Windows, Mac, Linux, iOS, Android, HTML5/WebGL and even Unity projects!

Volta is a WIP 2D game development framework for Luau written in C++. It is cross platform, currently only officially supports Windows, Linux and macOS (though macOS has no official builds, so you will have to compile the framework yourself for it). Android and iOS support is planned in the future.

A free and open-source, cross-platform game engine for creating 2D and 3D projects with Lua or C++. It is lightweight and promotes the simplest way to use the best performance of a data-oriented design.

An open-source SDK for Nintendo 64. It aims for a complete N64 programming experience while providing programmers with modern approach to programming and debugging.

2D game engine made on top of Flutter