The flexible game engine
The PHP Interpreter
Xash3D FWGS engine
An OpenGL RTS game engine written in C
A fully-featured OpenGL and GLFW extension for PHP
This is a re-implementation of the 1995 PSX game wipEout
A completely free, open-source, 2D game engine
Motor de juegos de aventura programable
The ioquake3 community effort to continue supporting/developing id's
An iOS & tvOS Frontend for Multiple Emulators
3D game engine/framework in C, with Luajit and Python bindings now
Go bindings for raylib, a simple and easy-to-use library
A free/open source client and automation tool for Ragnarok Online
Multi-Joint dynamics with Contact. A general purpose physics simulator
Simple DirectMedia Layer
A free and open-source Touhou Project fangame
Orx: Data-Driven Game Engine
Capstone disassembly/disassembler framework
CGL (C Game Library) is a multipurpose library
A modern, cross-platform Quake game engine based on FitzQuake.
SDL based generic 2D game engine
A WIP of a very cool game engine
0 A.D. is a free, open-source, cross-platform real-time strategy game.
A fun realistic multiplayer free-and-open-source first-person-shooter!