Aardappel, the creator of Sauerbraten has his own philosophy about this CUBE-inherited 3Dengine: Keep it simple! Well, that's what he did: He kept it simple. Although now the engine can visualize in Real 3D (CUBE couldn't), the concept still consists of the same simple, "cube"-based algorythm. That makes the game fast and... easy to modify. Custom maps are being added daily to the website and with each update of the Sauerbraten engine there come new multiplayer maps along with it. And thats because the engine is being distributed with an ingame-editor, which, after some time, is a great and easy tool for the creation of custom maps. For the experienced mod-developer it is no big challenge to replace some models or even add new ones to the game. And for the C++-Programmer the source code is being distributed, too. And that was not the only good news: Every 3d-engine programmer might be surprised to hear that the whole game(!) including the engine has no more than 8000 lines of code.
