HTML5 Phigros chart player/simulator
RPG Maker 2000/2003 and EasyRPG games interpreter
Aim assistance for blocks and mobs
Open-source Android/Desktop remake of Civ V
Open-source rhythm game
Classic overhead run-and-gun game
An open source re-implementation of RollerCoaster Tycoon 2
s&box is a modern game engine, built on Valve's Source 2
One of the best Prodigy hacks
Doom-based AI research platform for reinforcement learning
RetroArch is a frontend for emulators, game engines and media players.
Archipelago Multi-Game Randomizer and Server
The Ren'Py Visual Novel Engine
Fully async, multithreaded, predictive, open source, 3.01 reach
Multi Theft Auto is a game engine
The Oldschool Runescape API wrapper that does more
Endless Sky is a sandbox-style space exploration game
Access GameLift resources and integrate GameLift into your Unity game
Voxel game-creation platform with easy modding and game creation
Google maps for block game
Free and open source real-time strategy game
A game of dungeon exploration, combat and magic
The Shiptest Codebase
You can make it - Open Source MMORPG Platform
Minecraft map editor and mod