RetroArch is a frontend for emulators, game engines and media players.
Zig game engine & graphics toolkit
Fast, user-friendly cross-platform custom launcher for Minecraft
A game engine powered by python and panda3d
Descent 3 by Outrage Entertainment
A lightweight game server framework implemented with Actor Model
A dead simple 2D game engine for Go
2D JavaScript Physics Engine
Botcraft is a cross-platform C++ library to create bots
Gideros Release version
RTS game with the theme of Strategy by Design
FlightGear Flight Simulator: free open-source multiplatform flight sim
0 A.D. is a free, open-source, cross-platform real-time strategy game.
A free transportation simulator game
For exploring cellular automata like Conway's Game of Life.
xBRZ: "Scale by rules" - high quality image upscaling filter by Zenju
Odamex is a free, cross-platform, modern client-server Doom engine
3D Engine c++
A modern, cross-platform Quake game engine based on FitzQuake.
A cross-platform port of Hexen II game.
C64/Amiga emulator with shader and runAhead
Cross-platform real-time strategy game (3D)