GZDoom is a feature centric port for all Doom engine games
A certain block game
Command & Conquer: Remastered Collection
OptiScaler bridges upscaling/frame gen across GPUs
An unofficial PC port of the Xbox 360 version of Sonic Unleashed
Diablo build for modern operating systems
Voxel game-creation platform with easy modding and game creation
A tool for recompiling Xbox 360 games to native executables
Tool to statically recompile N64 games into native executables
UZDoom is a feature centric port for all Doom engine games
Open source clone of the Age of Empires II engine
Source code repository of the FreeOrion project
Botcraft is a cross-platform C++ library to create bots
RTSish Game Engine
Command and Conquer: Red Alert original source code
Injectable LUA scripting system, SDK generator, live property editor
A modern re-implementation of the classic DOS game Duke Nukem II
Cross-platform port of Arx Fatalis, a first-person role-playing game
OpenGL port of the classic 6dof 3D shooter Descent
Graphical hook for a D3D9-D3D12, OpenGL and Vulkan based games
Open RealStrategyGameLibrary (Engine)
Compatible client of Ace of Spades 0.75
Positional Audio Communication for Minecraft with Mumble
Tool for modding Red Orchestra 2