Thank you for your kind words! I'm glad you enjoyed the game.
There's one main trick used in Pauper's Bride to give the illusion of an active, dynamic stage: slightly-tweaked copies of the level.
Let's take an example: in the first scene, when you walk up to your mother in the top-left, she appears to look up; what has happened is that the tile right in front of her is a door to another room, one in which her sprite is looking up.
Then, after your conversation with her, there's a knock at the door. This only happens once you step back (which you'll naturally end up doing) and enter ANOTHER door behind you, which then takes you to a copy of the room with the "knocking" lines.
This is how most of the changes are done—I have invisible doors that take you to a copy of the room with slight changes in it. It creates the illusion of a more active, animated environment.
I hope this helps!