Thanks for the feedback. The demo linked from the home page is much more a demo of the site's "abilities" than a full course.
Once you finished the demo, did you try going through a "Learning module"? (tip: you don't really have to register... simply click the PokerGym logo in the upper-left corner). There are two courses which are fully available -- Counting Outs and Combos.
If you're signed in, you should see them on this page: