Very cool game.
I was enjoying it but not sure what to do after entering the building.
I don't know if you're talking about this, but after a couple of hours of submitting the game I noticed a bug on a plugin: basically some of the event triggers for the cut scene with The Hatted are broken, and will show an error when completed. If you activate this event it should work (I'll try to fix it!!)
If you're talking about the puzzle on that area, you basically need to find 3 items and put them in it's place.
If you re-enter the game your progress will be saved since the game auto saves. Hope this works!!