is there any documentation for this theme?

if not apart from this forum is there any were that shows all the different features?

Install the theme and then look at Atahualpa Theme Options in your dashboard. Plenty of documentation and examples.

I'll add a WIKI once the theme features and the code have settled, which will be soon. Right now the code is still changing quite a bit and new features are still being added or changed. Tutorials would get outdated within weeks