Most of them don't look to be inaccurate, though they're mere fact quizzes.
The "very difficult" one on Satanic rituals (by his own rating) was pretty simple. I guess a few of the questions might have been obscure but anyone fairly familiar with the text would have no problem.
"The devil I'll bring you," answered Hagen. "I have enough to carry with my shield and breastplate; my helm is bright, the sword is in my hand, therefore I bring you naught."