Put in the film reels, one at a time, and watch what they play. If you look closely, there are sometimes letters/numbers faintly visible on certain slides. I noticed from the first film reel i put in (unsure if the order of rooms visited dictates anything) There were the initials JD in an eye and the letter 5 on the next slide. From the next film reel I put in two different pictures showed the numbers 115 (10 points to anyone who guesses what this refers to) and 110 on the next one. After that I got downed before finding any more, but I haven't seen these mentioned before in discussion about the easter eggs from B01.