Glad you like it.
A little hint about the window:
Imagine you enter a floor, other than the wall that has an opening you just entered, there will be 3 other walls all hanging openings, the position of the openings should always be the same like when you see it outside.
A trick (SPOILER!!!) is to count how many openings are away from you that has a balcony and link to a staircase to go upward.