Very interesting game, especially the plot: I explored every conversation option so I could get more backstory. Iblis interested me the most; I would totally play a game revolving around her and her possible psychic/intuitive abilities!
I know I had a hard time finding the secret medals, so here is a non-spoiler small hint for those who are trying to find them: Think you've got all your info and know who the suspect is? Possess that suspect and explore some more even if you already did; you might find a new option!