GZDoom is a Doom source port based on ZDoom. It features an OpenGL renderer and lots of new features, among them:
* 3D floors
* Dynamic lights
* Quake2/Unreal style skyboxes
* True color texture support
* Model support (limited at the moment)
It also contains many bug fixes not present in the most recent ZDoom versions.
These details are provided for information only. No information here is legal advice and should not be used as such.