The picture of Wolfgang Ritter is actually a picture of Bill Davis, creative director at Sierra On-Line. It was featured in Sierra News Magazine Volume 3 Number 2: Summer 1990 in an article about him.
In the library of Schloss Ritter, we can hear the synopsis of 2 books on the occult. They are in the top shelf of the bookcase placed in the center of the wall behind the table. When Gabriel picks up 2 books (twice) of that shelf, the narrator will tell us the summary of the 2 books: Lycantrhopes (werewolves) and Vampirism, an obvious reference to GK2 and GK3. This Easter Egg also appeared in the original Gabriel Knight 1.
