For missing 2D graphs use the feature-request page on sourceforge.
3D support will follow after the release 1.0.0. See for more infos the road map site.
To run the demos on your system, go to a "demos" directory. This isn't installed. That's why you have to go to your install directory or, if you have an octplot repository on your system, go to this repository. Then you can enter e.g. line_demo (of course after toggling to OctPlot).
|line demo||text demo|
|specgram demo||bar demo|
|layer demo||contour demo|