The only reason Doomsday is faster is because it has *HARDWARE* Opengl support. I mean, the OpenGL is accellerated by the video card. We have no video card, so everything is rendered in software. This means this will make absolutely nothing faster (as in speed of execution), but it *could* make a lot of stuff faster (as in time to port over).
It all depends on if the port is good and fast. If it is, some OpenGL games could be ported, probaby, but the OpenGL software renderer will always be slower than if someone made a custom 3d engine for gp32.