The Sauerbraten Engine is the Cube Engine's successor. Sauerbraten got founded by Wouter "Aardappel" van Oortmerssen and received lots of interest from other developers. Like Cube, it features in-game map editing and cooperative editing over the internet. Unlike Cube, Sauerbraten has lots of eyecandy functionality, like normal-, specular- and parallax-mapping, glow shaders and shadows. One of the biggest changes is probably the use of lightmaps for level lighting, rather than fast vertex lighting like Cube did. Sauerbraten is licensed under the zlib/libpng License, which is compatible to the GPL.
Sauerbraten is also a complete game by itself, with single player missions, single player deathmatch (against an invasion of monsters) and many multiplayer modes (capture the flag, deathmatch, assassin, etc.). However it is not entirely free software as stray bits of multimedia included in it are proprietary. As of yet no one has released a complete free version of it.
This engine is also used for a RPG project, called Eisenstern. The default install of Sauerbraten includes several town maps for exploring. It is also used in a game called Red Eclipse.
Blood FrontierRed Eclipse
- Intensity Engine