The code looks quite complex but the ingame UI is easy to grasp and polished. After spending all my money I was concerned a bit about income but then it started coming and I didn't get low any more. I really liked the little touches like people standing in front of shop before buying something, going inside, or fading in and out as they use elevators.
Does the colour of people signify their desires? I haven't grasped much how good advertising is as it didn't seem to have much impact. Other than that I would just suggest somehow highlighting (just with bolder wall?) the main door into the mall as now people seem to all appear out of a normal wall.