evaluating user’s H5P behaviour

My website combines H5P with gamipress. H5P erxercises are open for all visitors, but if they register as users, they can earn points by completing H5P exercises with definied minimum scores.
Now, it frequently happens that people register but seem to do nothing afterwards. This puzzles me. One explanation would be that the H5P exercises I created are too difficult to reach the defined minimum scores. In this case their activities will not be recoreded in the gamipress log, so I cannot know whether they tried in vain to solve the H5P tasks.
H5P, however, apparently logs any completion of an exercise, regardless of the score reached. There is a menu item “My results” which shows me which exercises I completed while being logged in as administrator. Obviously, this information is useless to me.
If, however, I could access this H5P log for all users, possibly with user anonymity, I could see which exercises are often completed without reaching full score. Is there any way to do this? Perhaps by directly accessing the MySQL database? Searching there, however, I could not find the relevant set of data. If it is there, what is it called?

The page I need help with: [log in to see the link]