What would I need if I want to go for Tempest-like game with GD? I’d like to use GD as I think it is flexible and really can’t use any real 3d engine as every easy 3D game making IDE (3drad, Unity3d, UDK) is not for Linux (well, there IS Blender Game Engine bundled with Blender gfx software, but it doesn’t exactly have good performance - sure there were many good games made with it - YoFrankie, for others just search BGE on youtube, but it is hard to make good 3d game with it in comparison to other engines).
Also I know GD is capable of pseudo3d, as there is example of 3d engine bundled with it.