Very polished game with a very nice scope for a Jam!
Really nice take on the theme. It does work insanely good for a city builder mechanic. Seems appropriate and interesting enough to construct a game around it. Art is good, game tutors itself, controls are flawless and the music is just right!
Great entry! Had fun playing!
All the feedback below haven't affected the rating.
As a main point of improving the game after the Jam I see adding of some kind of challenge and punishment for the player. Maybe turn wise (random encounters messing with your buildings or dice to play around it) or more weight to the skipped turns (taking money away or use the decay mechanics every turn, not the successful ones), or even restricting a player by tiles (you cannot place all buildings, some of them are just too big).