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.
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"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."