A game engine powered by python and panda3d
Descent 3 by Outrage Entertainment
3D game engine/framework in C, with Luajit and Python bindings now
High performance UI layout library in C
Zig game engine & graphics toolkit
2D JavaScript Physics Engine
Orx: Data-Driven Game Engine
Full featured MUD server with all the trimmings.
Game engine supporting many 3D/2D formats and graphic effects
C++ lightweight cross-platform game engine
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A game engine for console based text games
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
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Web powered cross-platform 3D, WebXR game engine
scriptable game engine with built-in support for 2D graphics and sound
Multi-platform game engine similar to old Megaman with a stage editor
A generic 2D engine for any kind of game
TurboSphere is an easy to learn and powerful JS based game engine.
A 3D, fully concurrent game engine
3D game engine for C and C++
Open source, moddable game engine for the "Polygon Love 2" game
Javascript adventure game engine