Cube 2: Sauerbraten is a free multiplayer & singleplayer first person shooter, the successor of the Cube FPS.Much like the original Cube, the aim of this game is fun, old school deathmatch gameplay and also to allow map/geometry editing to be done cooperatively in-game.The engine supporting the game is entirely original in code & design, and its code is Open Source (ZLIB license, read the docs for more on how you can use the engine).