I've done all three episodes. I just couldn't resist letting those secrets remain shadowed. Once the maps arrive the most noticeable and helpful differences you will see are a teleport guide in Episode 1 - Room 8, a numbered lever sequence in Episode 2 - Room 16 and the entire maze layout in Episode 3 - Room 8. Also in Episode 3 is an extra room which you enter just after you go through Room 20. I don't believe it lol! that room wasn't mapped chortle!