Atmosphère is a work-in-progress customized firmware for the Nintendo
DOSBox Staging is a modern continuation of DOSBox
GZDoom is a feature centric port for all Doom engine games
Cross-platform 2D and 3D game engine with modular architecture
A free/open source client and automation tool for Ragnarok Online
API and runtime that allows access to VR hardware
Free game engine for development of desktop, mobile, and web games
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
Simple, open source crosshair application called AdrixCH
SnapKey: Open Source Alternative to Snap Tap & SOCD
Free and open-source emulator for Nintendo 64
A fun realistic multiplayer free-and-open-source first-person-shooter!
Modern Windows-optimized fork of the FCEUX NES/Famicom emulator.
Synthetic Vision/Sectional Maps for experimental aircraft.
Cross-platform port of Arx Fatalis, a first-person role-playing game
Amazon Lumberyard is a free AAA game engine
DeSmuME is a Nintendo DS emulator
2D Game Engine with Lua Scripting made on top of SFML
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.