Really fun game. I'm impressed you made this in 48 hours.
One thing I didn't like was counting tiles in building mode. Would be nice if there was a way to measure things there too.
Also I saw one of your QR codes, but unfortunately my phone didn't want to pick it up
(Edit: saw the other one, cool little easter egg)
Edit 2: So it seems there are a few things which make it really easy to guess where things are: The size of the placement board is always exactly how big the room is. And the walls seem to be more valuable than anything else (Because there are way more of them than other stuff).
One time I accidentally pressed start heist before I placed cameras and stuff but had the walls in place. I still got 75% and heist was successful, despite me not even marking where the treasure is...
Edit 3: You can literally win level 1 by just placing outside walls, and get 66% on second level.