BookWorm-Cheat Engine
Farm_Mania_HV-Cheat Engine
Fruit Ninja - Cheat Engine
Amazing Adventure-Cheat Engine
Pink Panther-Cheate Engine
Orx: Portable Game Engine
GemRB is a portable open-source implementation of the Infinity Engine
A free and open-source Touhou Project fangame
Game engine supporting many 3D/2D formats and graphic effects
The Open Toolkit library is a fast, low-level C# wrapper for OpenGL
A fun realistic multiplayer free-and-open-source first-person-shooter!
Arianne is an engine to develop multiplayer online games like Stendhal
Lucifer: The Ultimate Dev-Ecosystem
A frontend for GnGeo emulator written purely in Python
A development environment focused on modding
Rust library to create a Good Game Easily
DOOM / Heretic / Hexen source port with enhanced graphics and UI
Low-Level Game Engine for Retro Platforms
Portable game engine with main focus on point-and-click adventures
SJCE - free portable cross-platform graphical chess game, 100% Java.
Based on the raedwulf-et project
scriptable game engine with built-in support for 2D graphics and sound
NextGen Cheat Device
Multi-platform game engine similar to old Megaman with a stage editor