This and that
Please understand that I don't want to complain and mean this purely as feedback to the course authors, who have done a tremendously great job with this course.
That said: The skill "Demo" is for me one of the first big roadblocks I hit with every crown iteration. The variety of translations for "this" and "that" that the czech language has to offer is overwhelming, and their subtleties completely lost on me, no matter how often I look them up.
In case the course is being revised at some point, two questions/suggestions:
Do we really need to know all variations? How much would we miss if we only got "ten" and "tento"?
If that's unacceptable (which I'd accept, as I said, I can't remember the subtleties at this point, even if I hope I will one day): can they be spread over the course and not all introduced in one skill?
 With "crown iteration" I mean passes through the course. I have about 4/5 of the tree on crown level 1, 3/4 on level 2, less than half on level 3 and am just starting to push the first skills to level 4.
yes, we can spread the demos across more skills. "ten" is already taught earlier than the rest and partly overlaps with THE in addition to THAT. (did you try reading the tips and notes?)
the future staging and simplification of things like the demos will depend on what the team decides. my vote is to teach those that belong in CEFR A1 and bump the rest past the A1 part of the tree.
but this may or may not happen in version 2. we do not want to expose too much work to the A/B testing risk.