Oh, my! Well, I am glad you enjoyed this section of the game! A few elements that I felt were lost in The Guardian were a) Solving the puzzles before the candles shorted, b) His four 'pets', and the riddle that surrounded the nature of their names, and c) The Guardian passing himself off as King Endon. Though that last part might've been kept intact, the impact was lost because you were not actively solving the guardian's name (which is, if I remember, the main focus in the original book). Instead, the game took an approach that seemed similar to the Mirror of Fear saga in the anime (the 3 characters facing their fears). At least, it seemed that Lief was facing his fears (his family and friends forgetting him).
Something I can give the game credit for is giving most of the major characters and supporting characters a faceset (portrait when they speak). Unlike some games, which can only afford to give facesets to only the main cast.