It's got a good concept but it's way too simple at the moment. If you're careful you can stack buildings pretty much exactly on top of each other and the game lasts a long time. It could use more complexity, like how others mentioned weirder shaped buildings (and a wider base). I'd also suggest more stats for the player to try and manage? Like happiness for the citizens of the tower, or something.
I do love the scratchy scribbly art style, it definitely fits the cartoony tone of the game even if that's not really intentional